1bgl

From Proteopedia

Revision as of 06:50, 18 November 2007

BETA-GALACTOSIDASE (CHAINS A-H)

Overview

The beta-galactosidase from Escherichia coli was instrumental in the, development of the operon model, and today is one of the most commonly, used enzymes in molecular biology. Here we report the structure of this, protein and show that it is a tetramer with 222-point symmetry. The, 1,023-amino-acid polypeptide chain folds into five sequential domains, with an extended segment at the amino terminus. The participation of this, amino-terminal segment in a subunit interface, coupled with the, observation that each active site is made up of elements from two, different subunits, provides a structural rationale for the phenomenon of, alpha-complementation. The structure represents the longest polypeptide, chain for which an atomic structure has been determined. Our results show, that it is possible successfully to study non-viral protein crystals with, unit cell dimensions in excess of 500 A and with relative molecular masses, in the region of 2,000K per asymmetric unit. Non-crystallographic symmetry, averaging proved to be a very powerful tool in the structure, determination, as has been shown in other contexts.

About this Structure

1BGL is a Single protein structure of sequence from Escherichia coli with MG as ligand. The following page contains interesting information on the relation of 1BGL with [lac Repressor]. Active as Beta-galactosidase, with EC number 3.2.1.23 Full crystallographic information is available from OCA.

Reference

Three-dimensional structure of beta-galactosidase from E. coli., Jacobson RH, Zhang XJ, DuBose RF, Matthews BW, Nature. 1994 Jun 30;369(6483):761-6. PMID:8008071

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