2g23

From Proteopedia

Revision as of 08:47, 21 November 2007

The crystal structure of hexameric phenoxazinone synthase

Overview

The multicopper oxidase phenoxazinone synthase (PHS) catalyzes the, penultimate step in the biosynthesis of the antibiotic actinomycin D by, Streptomyces antibioticus. PHS exists in two oligomeric forms: a dimeric, form and a hexameric form, with older actinomycin-producing cultures, containing predominately the hexameric form. The structure of hexameric, PHS has been determined using X-ray diffraction to a resolution limit of, 2.30 A and is found to contain several unexpected and distinctive, features. The structure forms a hexameric ring that is centered on a, pseudo 6-fold axis and has an outer diameter of 185 A with a large central, cavity that has a diameter of 50 A. This hexameric structure is stabilized, by a long loop connecting two domains; bound to this long loop is a fifth, copper atom that is present as a type 2 copper. This copper atom is not, present in any other multicopper oxidase, and its presence appears to, stabilize the hexameric structure.

About this Structure

2G23 is a Single protein structure of sequence from Streptomyces antibioticus with CU, C2O and GOL as ligands. Full crystallographic information is available from OCA.

Reference

Structure of phenoxazinone synthase from Streptomyces antibioticus reveals a new type 2 copper center., Smith AW, Camara-Artigas A, Wang M, Allen JP, Francisco WA, Biochemistry. 2006 Apr 11;45(14):4378-87. PMID:16584173

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