Newsletter 06/2024 edited by Loredano Pollegioni

Do you have news concerning the D-amino acids field to announce? Is there a relevant published paper to mention? Write us and take the advantage of this bimonthly Newsletter.

The Editor’s pick selection of the most intriguing papers is highlighted in yellow.

D-AAs AND PATHOLOGIES:

DAAO Mutant Sites among Different Mice Strains and Their Effects on EnzymeActivity

Yu-Cong Z, Sheng-Ling F, Hao LProtein J. 2024 Nov 2. doi: 10.1007/s10930-024-10235-8. Online ahead of print.This study reports on a prokaryotic expression system for heterologous expression of mouse D-amino acidoxidase (mDAAO) in vitro. Two mutations in mDAAO encoding gene, in exons 2 (V64A) and 10 (R295H), werenon-synonymous mutations: these substitutions increased the affinity of DAAO with substrate and enhanced itscatalytic efficiency, as well as the affinity with the inhibitor CBIO.

Triiodothyronine acts on DAO to regulate pulmonary fibrosis progression byfacilitating cell senescence through the p53/p21 signaling pathway

GuoX, Xu K, Wang L, Ding L, Li W, Zhang X, Zhao W, Wang N, Wang G, Zhao W, Rosas I, Yu GFront Pharmacol. 2024 Sep 11;15:1433186. doi: 10.3389/fphar.2024.1433186.

This work reports that D-amino acid oxidase (DAAO) expression was downregulated in the lungs of idiopathicpulmonary fibrosis (IPF) patients and bleomycin (BLM)-induced fibrotic mice. Treatment with D-serine (D-Ser) orDAAO inhibitors promoted cell senescence through the p53/p21 pathway. Dao-/- mice showed an intensifiedfibrotic response, and the anti-fibrotic role of T3 was abolished. The authors concluded that the DAO-p53/p21axis might be a key anti-fibrotic pathway regulating the progress of fibrosis and facilitating the therapeutic roleof T3.

Physiology, Pathophysiology and Clinical Relevance of D-Amino AcidsDynamics: From Neurochemistry to Pharmacotherapy

Donoso MV, Catalán-Salas V, Pulgar-Sepúlveda R, Eugenín J, Huidobro-Toro JPChem Rec. 2024 Oct;24(10):e202400013. doi: 10.1002/tcr.202400013.

This is a review on the role of D-aspartate and D-serine, in proteins (i.e. the human eye crystallin, teeth, bone, … ) as well as in pathological conditions.

Serum D-asparagine concentration adjusted for eGFR could serve as a novel screening tool for urothelial carcinoma

Yamamoto A, Kawashima A, Sakai S, Mita M, Sassi N, Inoguchi S, Horibe Y, Yoshimura A, Tani M, Yutong L, Okuda Y, Oka T, Uemura T, Yamamichi G, Ishizuya Y, Hayashi T, Yamamoto Y, Kato T, Hatano, Kakuta Y(1), Imamura R, Takahara S, Kimura T, Nonomura N

Biochem Biophys Res Commun. 2024 Nov 12;733:150701. doi: 10.1016/j.bbrc.2024.150701.

The sensitivity of currently available screening tools for urothelial carcinoma (UC) remains unsatisfactory particularly at early stages. Here, the serum D-amino acid levels were measured in 108 and 192 patients with and without UC in the derivation cohort, and 15 and 25 patients with and without UC in the validation cohort. Serum D-Asn levels were significantly higher in patients with UC than in those without UC. A novel screening equation for the diagnosis of UC based on D-Asn levels in serum and estimated the glomerular filtration rate (eGFR) was established. This strategy combined with urinary occult blood, improved the diagnostic potential (sensitivity: 93.7%, specificity: 70.1%).

Mammalian D-Cysteine controls insulin secretion in the pancreas

Roychaudhuri R, West T, Bhattacharya S, Saavedra HG, Lee H, Albacarys L, Gadalla MM, Amzel M, Yang P, Snyder SH

Mol Metab. 2024 Oct 3;90:102043. doi: 10.1016/j.molmet.2024.102043

This study shows that endogenous D-cysteine (D-Cys) in the mammalian pancreas is a regulator of insulin secretion. D-Cys is synthesized by serine racemase (SR) and SR-/- mice produce 6 to 10-fold higher levels of insulin in the pancreas and plasma, including higher glycogen and ketone bodies in the liver. In glucose stimulated insulin secretion in mouse and human islets, equimolar amount of D-Cys resulted in higher inhibition of insulin secretion compared to D-serine. In mouse models of diabetes (Streptozotocin, STZ) and Non-Obese Diabetes (NOD) and human pancreas, the diabetic state resulted in higher levels of D-Cys compared to D- serine followed by increased expression of SR. SR-/- mice showed decreased cAMP in the pancreas, lower DNA methyltransferase enzymatic and promoter activities followed by reduced phosphorylation of CREB, resulting in decreased methylation of the Ins1 promoter.

Safety and efficacy of sodium benzoate for patients with mild Alzheimer’s disease: a systematic review and meta-analysis

Mansour MEM, Ali AHG, Ibrahim MHM, Mousa AIA, Negida AS

Nutr Neurosci. 2024 Oct 25:1-10. doi: 10.1080/1028415X.2024.2415867.

This review selected three randomized clinical trials (RCTs) aimed to investigate the safety and efficacy of sodium benzoate in AD patients, with a total of 306 patients. Sodium benzoate significantly improved the ADAS-cog score compared with placebo. The study concluded that sodium benzoate is a safe drug that may improve cognitive function in patients with early-stage Alzheimer’s disease. Further research with larger sample sizes and longer durations is necessary to validate these findings and assess safety and efficacy.

D-AAS & PHYSIOLOGICAL ROLES:

Excitatory  amino  acids  as  therapeutic  agents:  Reversing  neurodegenerative trajectory by tackling excitotoxicity

Dhurandhar Y, Tomar S, Namdeo KP, Bodakhe SH

Neurol Sci. 2024 Nov 15. doi: 10.1007/s10072-024-07880-3.

This review explores the role of D-amino acids in mitigating excitotoxicity, a process implicated in the pathogenesis of diseases such as Alzheimer’s disease. By providing alternative pathways for neuronal signaling and protecting against excitotoxic damage, D-amino acids offer a novel approach to reversing neurodegeneration. Next studies should focus on elucidating their mechanisms of action, evaluating their therapeutic potential, and developing effective delivery systems to optimize their neuroprotective effects.

D-AAS & BIOTECHNOLOGY:

Poly(vinyl alcohol) potentiating an inert D-amino acid-based drug for boron neutron capture therapy

Konarita K, Kanamori K, Suzuki M, Tokura D, Tanaka S, Honda Y, Nishiyama N, Nomoto T

J Control Release. 2024 Nov 10:S0168-3659(24)00762-4. doi: 10.1016/j.jconrel.2024.11.017.

This study shows that mixing with poly(vinyl alcohol) (PVA) unleashed latent potentials of D-amino acids in boron neutron capture therapy (BNCT). PVA formed boronate esters with seemingly useless boronated D-amino acids and induced tumor-associated amino acid transporter-superselective internalization and prolonged intracellular retention. The internalization was obtained by switching the internalization pathway from ineffective pass through the transporter to the transporter-mediated endocytosis. The boronate esters dissociated because of the acidic environment in the endo-/lysosome and elicited the stealthiness of the drugs. Notably, in a subcutaneous tumor model, this system reached high tumor-selective accumulation and induced drastic BNCT effects.

Whole-Tumor Clearing and Imaging of Intratumor Microbiota in Three Dimensions with miCDaL Strategy

Adv Sci (Weinh). 2024 Oct 8:e2400694. doi: 10.1002/advs.202400694.

In this paper, a modified iDISCO-CUBIC tissue clearing and D-amino acid microbiome labeling-based (miCDaL) strategy have been proposed, that integrates microbiota in situ labeling, tissue clearing, and whole-mount tissue imaging to visualize indigenous intratumor microbiota. The 3D biogeography of microbiota was successfully charted across various tumors at different developmental stages. By incorporating an immunostaining protocol, 3D imaging of the immunologic microenvironment is achieved in both murine and human mammary tumors that was previously assumed to be bacteria-free.

Enzyme  Cascade  with  Four  Enzymes  in  One  Pot  for  the  Synthesis  of  L- Phosphinothricin

Xu J, Xi Z, Zhao K, He C, Cheng F, Xue Y, Zheng Y

Advanced Synthesis and Catalysis. 2024, 366 (19): 4169 – 4177 doi: 10.1002/adsc.202400498

The enzymatic production of L-phosphinothricin (L-PPT) from the racemic D,L-PPT mixture is a green and environmentally friendly approach with significant potential. In this study, the oxidative deamination of D-PPT to 2-oxo-4-(hydroxymethylphosphinyl)butanoic acid (PPO) was gained using D-amino acid oxidase, followed by the catalytic reductive amination of PPO to L-PPT using phosphinothricin dehydrogenase. A “two-step one-pot” method was employed to link the optimized reactions, significantly shortening the production time: 97.7% yield of L-PPT with ee of L-PPT>99.9% after 5.5 h of reaction under 800 mM D,L-PPT catalytic conditions, was produced.

ENZYMES ACTIVE ON D-AAS:

Insights into the Functioning of the D-amino Acid Transaminase from Haliscomenobacter hydrossis via a Structural and Spectral Analysis of its Complex with 3-Aminooxypropionic Acid

Bakunova AK, Matyuta IO, Nikolaeva AY, Boyko KM, Khomutov AR, Bezsudnova EY, Popov VO Acta Naturae. 2024 Jul-Sep;16(3):18-24. doi: 10.32607/actanaturae.27496.

In the present work, the interaction between D-amino acid transaminase (a pyridoxal 5′-phosphate-dependent enzyme) from the bacterium Haliscomenobacter hydrossis and 3-aminooxypropionic acid was studied. The structural and spectral analyses of the ensuing complex allowed to clarify some features of the organization and functioning of the enzyme active site, and illustrate one of the mechanisms of inhibition by the specific substrate, D-glutamic acid.

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Incorporation of pyridoxal-5′-phosphate into the apoenzyme: A structural study of D-amino acid transaminase from Haliscomenobacter hydrossis

Bakunova AK, Matyuta IO, Minyaev ME, Boyko KM, Popov VO, Bezsudnova EY

Biochimica et Biophysica Acta – Proteins and Proteomics, 2025, 1873 (1), art. no. 141056 doi: 10.1016/j.bbapap.2024.141056

This work focuses on the holoenzyme-apoenzyme interconversion and the kinetics of pyridoxal-5′-phosphate (PLP) incorporation into the apoprotein of the transaminase from Haliscomenobacter hydrossis. PLP binding to the apoprotein was accelerated in the presence of substrates. Two crystal structures of the apoprotein were obtained: the apoprotein and the one obtained by soaking crystals of the holoenzyme in a phenylhydrazine solution. The mechanism of PLP association with the apoprotein was proposed to be a three steps process: anchoring of the PLP via the phosphate group, displacement of two loops, and Schiff-bonding between the PLP and the ε-amino group of the catalytic lysine residue.

Structural Analysis and Substrate Specificity of D-Carbamoylase from Pseudomonas

Paronyan M, Koloyan H, Aganyants H, Hambardzumyan A, Soghomonyan T, Avetisyan S, Kocharov S, Panosyan H, Sakanyan V, Hovsepyan A

BioTech (Basel). 2024 Oct 3;13(4):40. doi: 10.3390/biotech13040040.

The synthesis of enantiomeric forms of D-amino acids can be achieved by a two-step “hydantoinase process” based on the sequential catalysis of substrates by D-carbamoylase and D-hydantoinase. This work focuses on the structural features of D-carbamoylase from Pseudomonas. The purified His-tagged protein showed the highest activity towards N-carbamoyl-D-alanine and N-carbamoyl-D-tryptophan. Molecular docking analysis revealed the location of the substrate binding site and MD simulations showed that the binding pocket of the enzyme in complex with N-carbamoyl-D-tryptophan was stabilized within 100 nanoseconds: Arg176 and Asn173 formed hydrogen bonds between the enzyme and substrates.

D-AAS IN MICROORGANISMS:

Discovery, Biosynthesis, and Characterization of Rodencin, a Two-Component Lanthipeptide, Harboring D-Amino Acids Introduced by the Unusual Dehydrogenase RodJ(A)

Fu Y, Pateri E, Kuipers OP

J Nat Prod. 2024 Oct 25;87(10):2344-2354. doi: 10.1021/acs.jnatprod.4c00170. Epub 2024 Sep 20.

The enzymes for synthesis of lanthipeptides, a group of ribosomally synthesized and post-translationally modified peptides, serve as valuable tools for peptide bioengineering. This work focuses on a class II lanthipeptide biosynthetic gene cluster in a Bacillus strain, driving the biosynthesis of a two-component lanthipeptide (rodencin) containing D-Ala and D-Abu. The α-peptide of rodencin contains one dìD-Ala and the β-peptide features both D-amino acids. These are installed by dehydratases RodM1 and RodM2 and dehydrogenase RodJA, the activities of which were successfully reconstituted using a dedicated E. coli expression system.

D-AAS IN PEPTIDES AND PROTEINS:

A novel peptide-based tau aggregation inhibitor as a potential therapeutic forAlzheimer’s disease and other tauopathies

Aggidis A, Devitt G, Zhang Y, Chatterjee S, Townsend D, Fullwood NJ, Ortega ER, Tarutani A, Hasegawa M, Cooper A, Williamson P, Mendoza-Oliva A, Diamond MI, Mudher A, Allsop D Alzheimers Dement. 2024 Nov;20(11):7788-7804. doi: 10.1002/alz.14246.

Here, a retro-inverso D-amino peptide, RI-AG03 [Ac-rrrrrrrrGpkyk(ac)iqvGr-NH2], based on the 306VQIVYK311 of Tau hotspots which exhibit disease-relevant attributes was produced. The RI-AG03 effectively suppresses aggregation of multiple Tau species containing both hotspots in vitro and in vivo, is non-toxic, and suppresses aggregation-dependent neurodegenerative and behavioral phenotypes. It meets the requirements for an anti- aggregation Tau therapeutic and should be explored further for its disease-modifying potential for Tauopathies.

The oral pathogen Porphyromonas gingivalis gains tolerance to the antimicrobial peptide DGL13K by synonymous mutations in hagA

Gorr SU, Chen R, Abrahante JE, Joyce PBM

PLoS One. 2024 Oct 24;19(10):e0312200. doi: 10.1371/journal.pone.0312200.

Porphyromonas gingivalis is a main pathogen for periodontal disease. It is resistant to the antimicrobial peptide LGL13K but susceptible to the all-D-amino acid stereoisomer, DGL13K. Upon prolonged exposure to DGL13K, a novel non-pigmented mutant was isolated: the DGL13K-tolerant bacteria exhibited synonymous mutations in the hagA gene. The non-pigmented bacteria were deficient in hemagglutination and hemoglobin binding, suggesting that the HagA protein was not expressed. In vivo virulence was similar for wild-type and non- pigmented bacteria in the Galleria mellonella model.

Time-Responsive  Activity  of  Engineered  Bacteria  for  Local  Sterilization  and Biofilm Removal in Periodontitis

Bai Y, Guo HL, Hua T, Li B, Feng G, Zhang Z, Teng Y, Liu Y, Qian N, Zheng B Adv Healthc Mater. 2024 Oct 23:e2401190. doi: 10.1002/adhm.202401190.

The known drugs to treat periodontitis have difficulty penetrating complex biofilms. The biofilm-penetrating probiotic of E. coli Nissle 1917 is coated with D-amino acids and can penetrate biofilms. After the fusion of D- amino acids with the biofilm, EcN entered the plaque biofilm and produced antimicrobial peptides to kill Porphyromonas gingivalis and eliminate periodontitis under the action of hydrogen. The efficacy of EcN@DA-D in biofilm penetration and treatment of periodontitis was demonstrated in a rat model of periodontitis.

Teixobactin “Swapmers” with l Tail Stereochemistry Retain Antibiotic Activity

Griffin JH, Mendoza AT, Nowick JS

J Org Chem. 2024 Oct 18;89(20):15325-15330. doi: 10.1021/acs.joc.4c01674.

The D-L-L-D-D-L-L pattern of stereochemistry in residues 1-7 of the peptide antibiotic teixobactin is critical to its activity, yielding an unusual amphiphilic β-sheet like structure. Here, three D-amino acids in the tail were substituted with L-amino acids: swapping residues D-Gln4 and D-allo-Ile5 in O-acyl isopeptide prodrugs of teixobactin permits the introduction of L-stereochemistry with retention of antibiotic activity. Nevertheless, modifying the N-terminal stereochemistry results in a loss of antibiotic activity. 

A Nonlinear Peptide Topology for Synthetic Virions

Noble JE, Hsiao YW, Kepiro IE, De Santis E, Hoose A, Augagneur C, Lamarre B, Briones A, Hammond K, Bray DJ, Crain J, Ryadnov MG

ACS Nano. 2024 Oct 29;18(43):29956-29967. doi: 10.1021/acsnano.4c10662.

Here, a nonlinear de novo peptide topology for the assembly of synthetic virions based on cyclized amino-acid sequence in which polar L- and hydrophobic D-amino acid residues of the same-type alternate is reported. This arrangement introduces pseudo C4 symmetries of side chains within the same cyclopeptide ring and effectively encapsulates genetic cargo and promotes its intracellular delivery and a target genetic response. 

Binding of Peptides Containing D-Amino Acids to the Tsg101 Tumor Susceptibility Protein

Perez H, Chapagain PP, Gerstman BS

ChemistrySelect, 2024, 9 (38), art. no. e202402860 DOI: 10.1002/slct.202402860. 

Tsg101 is implicated in tumorigenesis and viral budding, and its inhibition through peptide binding is a potential therapeutic strategy. In order to enhance peptide stability against enzymatic degradation, peptides with terminal L-proline (also acetylated) and middle D-amino acids (also amidated) were generated. Molecular dynamics simulations were performed on the peptide PywP, showing a strong binding at a novel Tsg101 site, with variations of the D-form amino acid ′w’ in 18 of 21 tested peptides. These peptides contain hydrophilic residues, potentially improving solubility and therapeutic delivery.

Optimization of the Central α-Amino Acid in Cystobactamids to the Broad- Spectrum, Resistance-Breaking Antibiotic CN-CC-861

Kohnhäuser D, Seedorf T, Cirnski K, Heimann D, Coetzee J, Sordello S, Richter J, Stappert M, Sabuco J-F, Corbett D, Bacqué E, Rox K, Herrmann J, Vassort A, Müller R, Kirschning A, Brönstrup M

Journal of Medicinal Chemistry, 2024, 67 (19), pp. 17162 – 17190 DOI: 10.1021/acs.jmedchem.4c00927.

Cystobactamids exhibit broad-spectrum activity against Gram-negative and Gram-positive bacteria. In this work, the central amino acid was modified by 33 derivatives: L-amino acids were preferred over the D- enantiomers. The compound CN-CC-861, carrying a propargyl side chain, had more than 16-fold lower minimal inhibitory concentration values against Enterococcus faecalis, Staphylococci and Acinetobacter strains, compared to known analogues, and also maintained activity against multidrug-resistant enterococci, displayed strong bactericidal activity, moderate-low frequencies of resistance and in vivo efficacy in a neutropenic thigh infection model with E. coli.

D-AAS AND ANALYTICAL METHODS:

Advances in Chiral Metabolomic Profiling and Biomarker Discovery

Pandey R, Tiziani S

Methods Mol Biol. 2025;2855:85-101. doi: 10.1007/978-1-0716-4116-3_5.

Chiral metabolomics entails the enantioselective measurement of the metabolome present in a biological system. D-Amino acids and D-hydroxy acids are now emerging as novel signaling molecules and potential biomarkers for various disorders. Here, the pivotal role of chiral metabolic profiling studies in disease diagnosis, prognosis, and therapeutic interventions has been outlined, as well as the cutting-edge chromatographic and mass spectrometry methods that enable enantioselective analysis of chiral metabolites. 

An enzymatic reaction-based SERS saliva analysis microporous array chip for chiral differentiation and high-throughput detection of D-amino acids

Lu F, Li L, Shen K, Qian Y, Zhang P, Yang Y, Zhu Q, Huang Y, Yan C, Wei W Mikrochim Acta. 2024 Oct 8;191(11):653. doi: 10.1007/s00604-024-06733-2.

A Raman-active boronate modified surface-enhanced Raman scattering (SERS) microporous array chip based on the enzymatic reaction of D-amino acid oxidase (DAAO) was constructed for reliable, sensitive, and quantitative monitoring of D-proline and D-alanine in saliva. The I882 cm-1/I998 cm-1 ratio increased at higher content of D-AAs in the sample. The limits of detection were 10-14 µM throughout the linear range of 20-500 µM. The saliva detection suggested that this sensor could rapidly differentiate between early-stage gastric cancer patients and healthy individuals. 

Tuning the peroxidase-mimic activity of CuX-trithiocyanuric acid complexes for colorimetric detection of gastric cancer-associated D-amino acids

Gao X, Zhu J, Zhao J, Zhao L, Sun Y, Lin J, Hu M, Liu Y, Yang S, Liu J

Sensors and Actuators B: Chemical, 2025, 424, art. no. 136871 doi: 10.1016/j.snb.2024.136871

Chiral metabolomics entails the enantioselective measurement of the metabolome present in a biological system. D-Amino acids and D-hydroxy acids are now emerging as novel signaling molecules and potential biomarkers for various disorders. Here, the pivotal role of chiral metabolic profiling studies in disease diagnosis, prognosis, and therapeutic interventions has been outlined, as well as the cutting-edge chromatographic and mass spectrometry methods that enable enantioselective analysis of chiral metabolites. 

Enantiospecific profiling of D-amino acid for gastric cancer diagnosis by using a biocatalytic MHOF nanoreactor

Zhou Q, Zhang H, Zeng T, Yang J, Liang Q, Shi H, Yin Y, Li G.

Sensors and Actuators B: Chemical, 2025, 423, art. no. 136716 DOI: 10.1016/j.snb.2024.136716.

In this work, a nanoreactor based on mesoporous hydrogen-bonded organic framework (MHOF) has been fabricated for the enantiospecific profiling of D-amino acids. MHOFs act as the scaffold to organize the D- amino acid oxidase (DAAO) and horseradish peroxidase (HRP). Once D-AAs transport into MHOFs, the chromogenic reactions of 3,3′,5,5′-tetramethylbenzidine (TMB) and H2O2 is activated. This nanoreactor can be operated in complex solution and can be used for the profiling of D-AA levels in saliva samples collected from gastric cancer patients. 

Recent Advancements in the Characterization of D-Amino Acid and Isoaspartate Post-Translational Modifications

Okyem S, Sweedler JV

Mass Spectrom Rev. 2024 Nov 18. doi: 10.1002/mas.21916.

IIn this work, several mass spectrometry (MS) and ion mobility techniques are reported, as well as other methods such as chromatography, enzymatic enrichment, and labelling, to characterize modifications that does not change the mass of a peptide, such as amino acid isomerisation. The authors reported the challenges inherent to these analytical methods and prospective developments in bioinformatics and computational strategies. 

Enantiomer-Specific Stable Carbon and Nitrogen Isotopic Analyses of Underivatized Individual L- and D-Amino Acids by HPLC + HPLC Separation and Nano-EA/IRMS

Sun Y, Blattmann TM, Takano Y, Ogawa NO, Isaji Y, Ishikawa NF, Ohkouchi N Anal Chem. 2024 Nov 15. doi: 10.1021/acs.analchem.4c02851.

This paper reports on a novel method for stable carbon and nitrogen isotopic (δ13C and δ15N) analysis of underivatized amino acid (AA) enantiomers simultaneously, based on HPLC separation and off-line isotopic measurement. The separation of L- and D-enantiomers of 15 proteinogenous AAs was reported, with all L-ones eluting before the corresponding D-enantiomers. By coupling this column with a multidimensional HPLC system for isolating individual AAs, the enantiomers were determined in the peptidoglycan isolated from Gram-positive bacterium Bacillus subtilis. 

Structure Derivatization of IgG-Binding Peptides and Analysis of Their  Secondary Structure by Circular Dichroism Spectroscopy

Muguruma K, Fukuda A, Shida H, Taguchi A, Takayama K, Taniguchi A, Ito Y, Hayashi Y Chem Pharm Bull (Tokyo). 2024;72(9):831-837. doi: 10.1248/cpb.c24-00430.

This work focused on a structure derivatization of an immunoglobulin G (IgG)-binding peptide (15-IgBP), a β- hairpin-like cyclic peptide with a twisted β-strand and assessed the effect of the secondary structure on IgG- binding activity using circular dichroism (CD) spectra analysis. Derivatization at the Ala5 and Gly9 positions affected the secondary structure of 15-IgBP: the small methyl group at Ala5 is crucial for retaining the preferred secondary structure while Gly9 could be replaced by D-amino acids. Four potent affinity peptides for IgG binding (Kd = 4.24-5.85 nM). Furthermore, the Gly9 position can be substituted for D-Lys.

D-AAS AND FOOD:

Decoding the Molecular Mechanism of Sweet Taste of Amino Acids by Their Intrinsic Properties and Interactions with Human Sweet Taste Receptor

Wang Y, Tong M, Cao Z, Sun Z, Derkach T, Liu B

ChemistrySelect, 2024, 9 (37), art. no. e202403468 DOI: 10.1002/slct.202403468.

This work focuses on the molecular basis of sweet taste toward various amino acids: hydrophobic or dispersion force between side chains and the sweet taste receptor (Tas1R2/Tas1R3) plays a prominent role for eliciting sweetness. The interaction of 13 amino acids with the receptor indicates that amino and carboxyl glucophores interact with identical residues of receptor, while the hydrophobic side chains generate specific topological orientations with the receptor, determining their chirality selection and sweetness intensities. Molecular dynamics analysis showed that sweet D-amino acids move toward the hydrophobic transmembrane domain during activation with a higher number of contacts with the receptor compared to nonsweet L-enantiomers. 

Combination of a novel bacteriophage and D-serine effectively controls Vibrio parahaemolyticus growth in seafood

Miura D, Yamaki S, Tabuchi I. Kawai Y, Yamazaki K

Applied Food Research, 2024, 4 (2), art. no. 100558 DOI: 10.1016/j.afres.2024.100558.

Vibrio parahaemolyticus is a Gram-negative halophilic bacterium that causes food poisoning, especially in seafood for raw consumption, such as sashimi. In this work, the phage VF16 was evaluated for the effectiveness in combination with D‑serine in controlling V. parahaemolyticus. This combination fully inhibited the re-growth of

1. parahaemolyticus in the liquid medium and suppressed its growth in the scallop samples. No VF16-resistant mutants were isolated from the scallop samples treated with VF16 alone or in combination with D‑serine.

INFORMATION

The D-amino acids International Research Center “DAAIR“ has been established in Gerenzano (Varese, Italy) in 2019 with the aim to support and perform scientific research projects and activities on the field of D-amino acids. The Center, located inside the Fondazione Istituto Insubrico Ricerca per la Vita, is aimed to represent a pole of excellence at international level for dissemination and research involving the D-amino acids (Director Silvia Sacchi).

Info@d-aminoacids.com

director@d-aminoacids.com

D-AMINO ACIDS INTERNATIONAL RESEARCH CENTER

INFO@D-AMINOACIDS.COM