title: Crystallization and X-ray structure analysis of a thermostable penicillin G acylase from Alcaligenes faecalis.
abstract: The enzyme penicillin G acylase (EC 3.5.1.11) catalyzes amide-bond cleavage in benzylpenicillin (penicillin G) to yield 6-aminopenicillanic acid, an intermediate chemical used in the production of semisynthetic penicillins. A thermostable penicillin G acylase from Alcaligenes faecalis (AfPGA) has been crystallized using the hanging-drop vapour-diffusion method in two different space groups: C222(1), with unit-cell parameters a = 72.9, b = 86.0, c = 260.2 , and P4(1)2(1)2, with unit-cell parameters a = b = 85.6, c = 298.8 . Data were collected at 293 and the structure was determined using the molecular-replacement method. Like other penicillin acylases, AfPGA belongs to the N-terminal nucleophilic hydrolase superfamily, has undergone post-translational processing and has a serine as the N-terminal residue of the β-chain. A disulfide bridge has been identified in the structure that was not found in the other two known penicillin G cylase structures. The presence of the disulfide bridge is perceived to be one factor that confers higher stability to this enzyme.
authors.affiliation: Division of Biochemical Sciences, National Chemical Laboratory, Pune 411 008, India.
authors.forename: Nishant Kumar
authors.initials: NK
authors.lastname: Varshney
authors.forename: R Suresh
authors.initials: RS
authors.lastname: Kumar
authors.forename: Zoya
authors.initials: Z
authors.lastname: Ignatova
authors.forename: Asmita
authors.initials: A
authors.lastname: Prabhune
authors.forename: Archana
authors.initials: A
authors.lastname: Pundle
authors.forename: Eleanor
authors.initials: E
authors.lastname: Dodson
authors.forename: C G
authors.initials: CG
authors.lastname: Suresh
mesh_terms: D042481:Alcaligenes faecalis / Q000201:enzymology*; D003460:Crystallization; D018360:Crystallography, X-Ray; D006358:Hot Temperature; D008958:Models, Molecular; D010399:Penicillin Amidase / Q000737:chemistry*; D020836:Protein Structure, Quaternary; D017434:Protein Structure, Tertiary
chemical_list: D010399:Penicillin Amidase