Pyridoxamine-pyruvate aminotransferase is a PLP (pyridoxal 5'-phosphate) (a coenzyme form of vitamin B6)-independent aminotransferase which catalyses a reversible transamination reaction between pyridoxamine and pyruvate to form pyridoxal and L-alanine. The gene encoding the enzyme has been identified, cloned and overexpressed for the first time. The mlr6806 gene on the chromosome of a symbioti...

The degree of hydroxylation of the lysine residue located in both ocland C2chains of collagen in the N-terminal, non-helical telopeptide region of the molecule has been determined in collagen from various sources after isolation of the peptides (aland ex2-CBI) that contain the lysine residue in question and are obtained by cyanogen bromide cleavage of collagen acland X2-chains respectively. As ...

Transglutaminase (TGase) from Streptomyces mobaraensis is a Ca(2+) independent enzyme that cross-links proteins to high molecular weight aggregates. A dispase autolysis inducing protein (DAIP) was identified as an intrinsic TGase substrate exhibiting accessible glutamine and lysine residues. DAIP modification during culture by TGase resulted in deamidation of reactive glutamines, formation of g...

By site-directed mutagenesis of the cloned human glucose-6-phosphate dehydrogenase cDNA, lysine 205 (the residue that after reacting with pyridoxal-5'-phosphate renders inactive enzyme) was mutated to threonine (K205T) to remove the amino group, or to arginine (K205R) to displace the position of the amino group, in order to analyze the role of its nucleophilic group in position epsilon. Compare...

A hypothesis is proposed for the preferential ionization/protonation of arginine residues in metastable protein ions. This phenomenon has significant consequences detection fragments resulting from polypeptide backbone cleavage. Preferential ionization at (when present) based upon MS/MS analysis singly charged/protonated ions: YahO, CspC, CspE, B-subunit Shiga toxin 2 and thioredoxin, that have...

Elongation factor P (EF-P) is a translation factor of unknown function that has been implicated in a great variety of cellular processes. Here, we show that EF-P prevents ribosome from stalling during synthesis of proteins containing consecutive prolines, such as PPG, PPP, or longer proline strings, in natural and engineered model proteins. EF-P promotes peptide-bond formation and stabilizes th...

The E1 protein is a multifunctional, origin-binding helicase that is essential for replication of papillomaviruses. Recently, bovine papillomavirus E1 was shown to be post-translationally modified by the addition of the SUMO-1 polypeptide. Here we show that the site of sumoylation maps to lysine residue 514. This lysine and the flanking sequences are well conserved in human papillomavirus (HPV)...

Alignments of orthologous protein sequences convey a complex picture. Some positions are utterly conserved whilst others have diverged to variable degrees. Amongst the latter, many are non-exchangeable between extant sequences. How do functionally critical and highly conserved residues diverge? Why and how did these exchanges become incompatible within contemporary sequences? Our model is phosp...

Homocitrate synthase (HCS) catalyzes aldol-type condensation of acetyl coenzyme A (acetyl-CoA) and alpha-ketoglutarate (alpha-KG) to synthesize homocitrate (HC), which is the first and committed step in the lysine biosynthetic pathway through alpha-aminoadipate. As known in most enzymes catalyzing the first reactions in amino acid biosynthetic pathways, HCS is regulated via feedback inhibition ...