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Structural characterization of the entire 1.3S subunit of transcarboxylase from Propionibacterium shermanii
Author(s) -
Reddy D. Venkat,
Rothemund Sven,
Sönnichsen Frank D.,
Shenoy Bhami C.,
Carey Paul R.
Publication year - 1998
Publication title -
protein science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.353
H-Index - 175
eISSN - 1469-896X
pISSN - 0961-8368
DOI - 10.1002/pro.5560071013
Subject(s) - heteronuclear molecule , propionibacterium , homonuclear molecule , chemistry , protein secondary structure , stereochemistry , crystallography , nuclear magnetic resonance spectroscopy , structural similarity , protein subunit , protein structure , amide , biochemistry , molecule , biology , organic chemistry , bacteria , gene , genetics
Transcarboxylase (TC) from Propionibacterium shermanii , a biotin‐dependent enzyme, catalyzes the transfer of a carboxyl group from methylmalonyl‐CoA to pyruvate in two partial reactions. Within the multisubunit enzyme complex, the 1.3S subunit functions as the carboxyl group carrier. The 1.3S is a 123‐amino acid polypeptide (12.6 kDa), to which biotin is covalently attached at Lys 89. We have expressed 1.3S in Escherichia coli with uniform 15 N labeling. The backbone structure and dynamics of the protein have been characterized in aqueous solution by three‐dimensional heteronuclear nuclear magnetic resonance (NMR) spectroscopy. The secondary structure elements in the protein were identified based on NOE information, secondary chemical shifts, homonuclear 3 Jhnhα coupling constants, and amide proton exchange data. The protein contains a predominantly disordered N‐terminal half, while the C‐terminal half is folded into a compact domain comprising eight β‐strands connected by short loops and turns. The topology of the C‐terminal domain is consistent with the fold found in both carboxyl carrier and lipoyl domains, to which this domain has approximately 26‐30% sequence similarity.