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1bnc
From Proteopedia
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| , resolution 2.4Å | |||||||
|---|---|---|---|---|---|---|---|
| Ligands: | |||||||
| Activity: | Biotin carboxylase, with EC number 6.3.4.14 | ||||||
| Coordinates: | save as pdb, mmCIF, xml | ||||||
THREE-DIMENSIONAL STRUCTURE OF THE BIOTIN CARBOXYLASE SUBUNIT OF ACETYL-COA CARBOXYLASE
Overview
Acetyl-CoA carboxylase is found in all animals, plants, and bacteria and catalyzes the first committed step in fatty acid synthesis. It is a multicomponent enzyme containing a biotin carboxylase activity, a biotin carboxyl carrier protein, and a carboxyltransferase functionality. Here we report the X-ray structure of the biotin carboxylase component from Escherichia coli determined to 2.4-A resolution. The structure was solved by a combination of multiple isomorphous replacement and electron density modification procedures. The overall fold of the molecule may be described in terms of three structural domains. The N-terminal region, formed by Met 1-Ile 103, adopts a dinucleotide binding motif with five strands of parallel beta-sheet flanked on either side by alpha-helices. The "B-domain" extends from the main body of the subunit where it folds into two alpha-helical regions and three strands of beta-sheet. Following the excursion into the B-domain, the polypeptide chain folds back into the body of the protein where it forms an eight-stranded antiparallel beta-sheet. In addition to this major secondary structural element, the C-terminal domain also contains a smaller three-stranded antiparallel beta-sheet and seven alpha-helices. The active site of the enzyme has been identified tentatively by a difference Fourier map calculated between X-ray data from the native crystals and from crystals soaked in a Ag+/biotin complex. Those amino acid residues believed to form part of the active site pocket include His 209-Glu 211, His 236-Glu 241, Glu 276, Ile 287-Glu 296, and Arg 338.2+ represents the first X-ray model of a biotin-dependent carboxylase.
About this Structure
1BNC is a Single protein structure of sequence from Escherichia coli. Full crystallographic information is available from OCA.
Reference
Three-dimensional structure of the biotin carboxylase subunit of acetyl-CoA carboxylase., Waldrop GL, Rayment I, Holden HM, Biochemistry. 1994 Aug 30;33(34):10249-56. PMID:7915138
Page seeded by OCA on Thu Mar 20 10:13:15 2008
