Interaction between Monobactams and Streptomyces R61 dd-Carboxypeptidase
نویسندگان
چکیده
منابع مشابه
Molecular weight and amino acid composition of the exocellular DD-carboxypeptidase-transpeptidase of Streptomyces R61.
A procedure allowing the purification of milligram amounts of the exocellular dd-carboxypeptidase-transpeptidase from Streptomyces R61 to protein homogeneity (95% purity) is described. The isolated protein has a molecular weight of about 38000 and consists of one polypeptide chain. Its amino acid composition is presented.
متن کاملFluorescence and circular dichroism studies on the Streptomyces R61 DD-carboxypeptidase-transpeptidase. Penicillin binding by the enzyme.
The circular dichroism of the dd-carboxypeptidase-transpeptidase from Streptomyces R61 shows in the near u.v. a set of weak extrema at 289nm (positive) and at 282, 275 and 268nm (all negative). In the far u.v. it shows negative extrema at 217-218 and 208nm, crossover at 202nm and a positive maximum at about 194nm. The u.v. absorption of the enzyme shows it to contain tyrosine and tryptophan in ...
متن کاملMechanism of action of DD-peptidases: role of asparagine-161 in the Streptomyces R61 DD-peptidase.
The role of residue Asn-161 in the interaction between the Streptomyces R61 DD-peptidase and various substrates or beta-lactam inactivators was probed by site-directed mutagenesis. The residue was successively replaced by serine and alanine. In the first case, acylation rates were mainly affected with the peptide and ester substrates but not with the thiol-ester substrates and beta-lactams. How...
متن کاملThe mechanism of action of DD-peptidases: the role of tyrosine-159 in the Streptomyces R61 DD-peptidase.
Tyrosine-159 of the Streptomyces R61 penicillin-sensitive DD-peptidase was replaced by serine or phenylalanine. The second mutation yielded a very poorly active protein whose rate of penicillin binding was also drastically decreased, except for the reactions with nitrocefin and methicillin. The consequences of the first mutation were more surprising, since a large proportion of the thiolesteras...
متن کاملThe mechanism of action of DD-peptidases: the role of Threonine-299 and -301 in the Streptomyces R61 DD-peptidase.
The side chains of residues Thr299 and Thr301 in the Streptomyces R61 DD-peptidase have been modified by site-directed mutagenesis. These amino acids are part of a beta-strand which forms a wall of the active-site cavity. Thr299 corresponds to the second residue of the Lys-Thr(Ser)-Gly triad, highly conserved in active-site beta-lactamases and penicillin-binding proteins (PBPs). Modification of...
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ژورنال
عنوان ژورنال: European Journal of Biochemistry
سال: 2005
ISSN: 0014-2956,1432-1033
DOI: 10.1111/j.1432-1033.1982.tb06622.x