1hqb
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(New page: 200px<br /><applet load="1hqb" size="450" color="white" frame="true" align="right" spinBox="true" caption="1hqb" /> '''TERTIARY STRUCTURE OF APO-D-ALANYL CARRIER P...)
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Revision as of 14:37, 20 November 2007
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TERTIARY STRUCTURE OF APO-D-ALANYL CARRIER PROTEIN
Overview
The D-alanylation of lipoteichoic acid (LTA) allows the Gram-positive, organism to modulate its surface charge, regulate ligand binding, and, control the electromechanical properties of the cell wall. The, incorporation of D-alanine into LTA requires the D-alanine:D-alanyl, carrier protein ligase (AMP-forming) (Dcl) and the carrier protein (Dcp)., The high-resolution solution structure of the 81-residue (8.9 kDa) Dcp has, been determined by multidimensional heteronuclear NMR. An ensemble of 30, structures was calculated using the torsion angle dynamics approach of, DYANA. These calculations utilized 3288 NOEs containing 1582 unique, nontrivial NOE distance constraints. Superposition of residues 4-81 on the, mean structure yields average atomic rmsd values of 0.43 +/- 0.08 and 0.86, +/- 0.09 A for backbone and non-hydrogen atoms, respectively. The solution, structure is composed of three alpha-helices in a bundle with additional, short 3(10)- and alpha-helices in intervening loops. Comparisons of the, three-dimensional structure with the acyl carrier proteins involved in, fatty acid, polyketide, and nonribosomal peptide syntheses support the, conclusion that Dcp is a homologue in this family. While there is, conservation of the three-helix bundle fold, Dcp has a higher enthalpy of, unfolding and no apparent divalent metal binding site(s), features that, distinguish it from the fatty acid synthase acyl carrier protein of, Escherichia coli. This three-dimensional structure also provides insights, into the D-alanine ligation site recognized by Dcl, as well as the site, which may bind the poly(glycerophosphate) acceptor moiety of, membrane-associated LTA.
About this Structure
1HQB is a Single protein structure of sequence from Lactobacillus casei. Full crystallographic information is available from OCA.
Reference
Biosynthesis of D-alanyl-lipoteichoic acid: the tertiary structure of apo-D-alanyl carrier protein., Volkman BF, Zhang Q, Debabov DV, Rivera E, Kresheck GC, Neuhaus FC, Biochemistry. 2001 Jul 10;40(27):7964-72. PMID:11434765
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