PURPOSE The aspartyl (Asp) residues 58 and 151 in αA-crystallin, and Asp36 and Asp62 in αB-crystallin in human lenses are known to be highly isomerized with aging. We investigate structural environments of these isomerizable aspartyl residues in α-crystallins of human lenses. METHODS To perform limited proteolysis experiments of purified human αA- and αB-crystallins, endoproteinase Asp-N (EC ...

The predatory bacterium Bdellovibrio bacteriovorus preys on other Gram-negative bacteria and was predicted to be an asparagine auxotroph. However, despite encoding asparaginyl-tRNA synthetase and glutaminyl-tRNA synthetase, B. bacteriovorus also contains the amidotransferase GatCAB. Deinococcus radiodurans, and Thermus thermophilus also encode both of these aminoacyl-tRNA synthetases with GatCA...

objective: the secreted aspartic proteinases (sap2) of candida albicans has prominent role on candida adherence, invasion, and pathogenicity. the aim of this study was cloning, expression and characterizing of sap2 enzyme. also in this study for the first time, the expression system p. pasturis was used for expressing the recombinant protein. materials and methods: c. albicans sap2 gene was am...

Nonenzymatic intramolecular reactions can result in the deamidation, isomerization, and racemization of protein and peptide asparaginyl and aspartyl residues via succinimide intermediates. To understand the sequence dependence of these reactions, we measured the rate of succinimide formation in a series of synthetic peptides at pH 7.4. These peptides (Val-Tyr-Pro-X-Y-Ala) contained an internal ...

The human pathogen Staphylococcus aureus is an asparagine prototroph despite its genome not encoding an asparagine synthetase. S. aureus does use an asparaginyl-tRNA synthetase (AsnRS) to directly ligate asparagine to tRNA(Asn). The S. aureus genome also codes for one aspartyl-tRNA synthetase (AspRS). Here we demonstrate the lone S. aureus aspartyl-tRNA synthetase has relaxed tRNA specificity a...