1bdo

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spinqualitylabelsall models 1bdo, resolution 1.8Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image

STRUCTURE OF THE BIOTINYL DOMAIN OF ACETYL-COENZYME A CARBOXYLASE DETERMINED BY MAD PHASING

Overview

BACKGROUND: Acetyl-coenzyme A carboxylase catalyzes the first committed, step of fatty acid biosynthesis. Universally, this reaction involves three, functional components all related to a carboxybiotinyl intermediate. A, biotinyl domain shuttles its covalently attached biotin prosthetic group, between the active sites of a biotin carboxylase and a carboxyl, transferase. In Escherichia coli, the three components reside in separate, subunits: a biotinyl domain is the functional portion of one of these, biotin carboxy carrier protein (BCCP). RESULTS: We have expressed natural, and selenomethionyl (Se-met) BCCP from E. coli as biotinylated recombinant, proteins, proteolyzed them with subtilisin Carlsberg to produce the, biotinyl domains BCCP and Se-met BCCPsc, determined the crystal structure, of Se-met BCCPsc using a modified version of the multiwavelength anomalous, diffraction (MAD) phasing protocol, and refined the structure for the, natural BCCPsc at 1.8 A resolution. The structure may be described as a, capped beta sandwich with quasi-dyad symmetry. Each half contains a, characteristic hammerhead motif. The biotinylated lysin is located at a, hairpin beta turn which connects the two symmetric halves of the molecule, and its biotinyl group interacts with a non-symmetric protrusion from the, core. CONCLUSIONS: This first crystal structure of a biotinyl domain helps, to unravel the central role of such domains in reactions catalyzed by, biotin-dependent carboxylases. The hammerhead structure observed twice in, BCCPsc may be regarded as the basic structural motif of biotinyl and, lipoyl domains of a superfamily of enzymes. The new MAD phasing techniques, developed in the course of determining this structure enhance the power of, the MAD method.

About this Structure

1BDO is a Single protein structure of sequence from Escherichia coli with BTN as ligand. Active as Acetyl-CoA carboxylase, with EC number 6.4.1.2 Full crystallographic information is available from OCA.

Reference

Structure of the biotinyl domain of acetyl-coenzyme A carboxylase determined by MAD phasing., Athappilly FK, Hendrickson WA, Structure. 1995 Dec 15;3(12):1407-19. PMID:8747466

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