Solution Structure of 4′-Phosphopantetheine-GmACP3 from Geobacter metallireducens: A Specialized Acyl Carrier Protein with Atypical Structural Features and a Putative Role in Lipopolysaccharide Biosynthesis

被引：6

作者：

Ramelot, Theresa A. ^{[1
]}

Smola, Matthew J. ^{[1
]}

Lee, Hsiau-Wei ^{[2
]}

Ciccosanti, Colleen ^{[3
]}

Hamilton, Keith ^{[3
]}

Acton, Thomas B. ^{[3
]}

Xiao, Rong ^{[3
]}

Everett, John K. ^{[3
]}

Prestegard, James H. ^{[2
]}

Montelione, Gaetano T. ^{[3
,4
]}

Kennedy, Michael A. ^{[1
]}

机构：

[1] Miami Univ, Dept Chem & Biochem, Oxford, OH 45056 USA

[2] Univ Georgia, Complex Carbohydrate Res Ctr, NE Struct Genom Consortium, Athens, GA 30602 USA

[3] Rutgers State Univ, Dept Mol Biol & Biochem, Ctr Adv Biotechnol & Med, NE Struct Genom Consortium, Piscataway, NJ 08854 USA

[4] Univ Med & Dent New Jersey, Robert Wood Johnson Med Sch, Dept Biochem, Piscataway, NJ 08854 USA

来源：

BIOCHEMISTRY | 2011年 / 50卷 / 09期

基金：

美国国家卫生研究院;

关键词：

FATTY-ACID SYNTHESIS; ESCHERICHIA-COLI; BACKBONE DYNAMICS; GENOMICS CONSORTIUM; PRODUCTION PLATFORM; STRUCTURE QUALITY; HOLO-FORMS; NMR; SYNTHASE; BINDING;

D O I：

10.1021/bi101932s

中图分类号：

Q5 [生物化学]; Q7 [分子生物学];

学科分类号：

071010 ; 081704 ;

摘要：

GmACP3 from Geobacter metallireducens is a specialized acyl carrier protein (ACP) whose gene, gmet_2339, is located near genes encoding many proteins involved in lipopolysaccharide (LPS) biosynthesis, indicating a likely function for GmACP3 in LPS production. By overexpression in Escherichia coli, about 50% holo-GmACP3 and 50% apo-GmACP3 were obtained. Apo-GmACP3 exhibited slow precipitation and non-monomeric behavior by N-15 NMR relaxation measurements. Addition of 4'-phosphopantetheine (4'-PP) via enzymatic conversion by E. coli holo-ACP synthase resulted in stable > 95% holo-GmACP3 that was characterized as monomeric by N-15 relaxation measurements and had no indication of conformational exchange. We have determined a high-resolution solution structure of holo-GmACP3 by standard NMR methods, including refinement with two sets of NH residual dipolar couplings, allowing for a detailed structural analysis of the interactions between 4'-PP and GmACP3. Whereas the overall four helix bundle topology is similar to previously solved ACP structures, this structure has unique characteristics, including an ordered 4'-PP conformation that places the thiol at the entrance to a central hydrophobic cavity near a conserved hydrogen-bonded Trp-His pair. These residues are part of a conserved WDSLxH/N motif found in GmACP3 and its orthologs. The helix locations and the large hydrophobic cavity are more similar to medium- and long-chain acyl-ACPs than to other apo- and holo-ACP structures. Taken together, structural characterization along with bioinformatic analysis of nearby genes suggests that GmACP3 is involved in lipid A acylation, possibly by atypical long-chain hydroxy fatty acids, and potentially is involved in synthesis of secondary metabolites.

引用

页码：1442 / 1453

页数：12