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Type: Journal article
Title: Covalent Modification of an Exposed Surface Turn Alters the Global Conformation of the Biotin Carrier Domain of Escherichia coli Acetyl-CoA Carboxylase
Author: Chapman-Smith, A.
Forbes, B.
Wallace, J.
Cronan, J.
Citation: Journal of Biological Chemistry, 1997; 272(41):26017-26022
Publisher: Elsevier BV
Issue Date: 1997
ISSN: 0021-9258
Abstract: We have studied the apo (unbiotinylated) and holo (biotinylated) forms of BCCP87, an 87-residue COOH-terminal peptide comprising the biotin carrier domain of the biotin carboxyl carrier protein subunit of Escherichia coli acetyl-CoA carboxylase. The apo protein spontaneously formed disulfide-linked dimers and was modified readily by sulfhydryl reagents, whereas the holo protein remained monomeric and was unreactive toward sulfhydryl reagents unless a protein denaturant was present. These data indicated that the single cysteine residue of the domain (Cys-116) was much more reactive in the apo form of the protein. Incubation of apoBCCP87 with biotin ligase for different times, followed by reaction with fluorescein-5-maleimide, clearly showed that the loss of Cys-116 reactivity was the result of modification with biotin. In addition, reaction of Cys-116 with 5,5'-dithiobis(2-nitrobenzoic acid) showed that apoBCCP87 denatured at lower urea concentrations than holoBCCP87. We also found that apoBCCP87 was at least 10-fold more sensitive than the holo form to proteolysis by a range of proteases. Identification of the cleavage sites indicated that the differences in protease sensitivity could not be attributed to shielding of susceptible bonds by the biotin moiety of the holo protein. These data indicate that a conformational change accompanies biotinylation of the biotin domain. Thus, modification of a beta-turn protruding from the protein surface results in alteration of the overall structure of this protein domain.
Keywords: Escherichia coli
Acetyl-CoA Carboxylase
Peptide Fragments
Carrier Proteins
Chromatography, High Pressure Liquid
Binding Sites
Amino Acid Sequence
Protein Conformation
Surface Properties
Models, Molecular
Molecular Sequence Data
Fatty Acid Synthase, Type II
DOI: 10.1074/jbc.272.41.26017
Appears in Collections:Aurora harvest 7
Biochemistry publications

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