2CEX

Structure of a sialic acid binding protein (SiaP) in the presence of the sialic acid acid analogue Neu5Ac2en

2CEX の概要

• エントリーDOI: 10.2210/pdb2cex/pdb
• 関連するPDBエントリー: 2CEY
• 分子名称: PROTEIN HI0146, ZINC ION, 2-DEOXY-2,3-DEHYDRO-N-ACETYL-NEURAMINIC ACID, ... (5 entities in total)
• 機能のキーワード: esr, periplasmic binding protein, tripartite atp-independent periplasmic (trap)transport, virulence factor, transport, periplasmic
• 由来する生物種: HAEMOPHILUS INFLUENZAE
• 細胞内の位置: Periplasm (Probable): P44542
• タンパク質・核酸の鎖数: 4
• 化学式量合計: 137774.98

構造登録者

Muller, A.,Severi, E.,Mulligan, C.,Watts, A.G.,Kelly, D.J.,Wilson, K.S.,Wilkinson, A.J.,Thomas, G.H. (登録日: 2006-02-10, 公開日: 2006-05-15, 最終更新日: 2024-05-08)

主引用文献

Muller, A.,Severi, E.,Mulligan, C.,Watts, A.G.,Kelly, D.J.,Wilson, K.S.,Wilkinson, A.J.,Thomas, G.H.
Conservation of Structure and Mechanism in Primary and Secondary Transporters Exemplified by Siap, a Sialic Acid Binding Virulence Factor from Haemophilus Influenzae
J.Biol.Chem., 281:22212-, 2006

PubMed Abstract: Extracytoplasmic solute receptors (ESRs) are important components of solute uptake systems in bacteria, having been studied extensively as parts of ATP binding cassette transporters. Herein we report the first crystal structure of an ESR protein from a functionally characterized electrochemical ion gradient dependent secondary transporter. This protein, SiaP, forms part of a tripartite ATP-independent periplasmic transporter specific for sialic acid in Haemophilus influenzae. Surprisingly, the structure reveals an overall topology similar to ATP binding cassette ESR proteins, which is not apparent from the sequence, demonstrating that primary and secondary transporters can share a common structural component. The structure of SiaP in the presence of the sialic acid analogue 2,3-didehydro-2-deoxy-N-acetylneuraminic acid reveals the ligand bound in a deep cavity with its carboxylate group forming a salt bridge with a highly conserved Arg residue. Sialic acid binding, which obeys simple bimolecular association kinetics as determined by stopped-flow fluorescence spectroscopy, is accompanied by domain closure about a hinge region and the kinking of an alpha-helix hinge component. The structure provides insight into the evolution, mechanism, and substrate specificity of ESR-dependent secondary transporters that are widespread in prokaryotes.

PubMed: 16702222
DOI: 10.1074/JBC.M603463200

実験手法

X-RAY DIFFRACTION (2.2 Å)