3QE5

Complete structure of Streptococcus mutans Antigen I/II carboxy-terminus

3QE5 の概要

• エントリーDOI: 10.2210/pdb3qe5/pdb
• 関連するPDBエントリー: 2WZA 3IOX 3IPK
• 分子名称: Major cell-surface adhesin PAc, CALCIUM ION, MAGNESIUM ION, ... (5 entities in total)
• 機能のキーワード: de-variant immunoglobulin-like fold, igg-like fold, adherence to human tooth, salivary agglutinin, extracellular, streptococcus, antigen i/ii, cell adhesion
• 由来する生物種: Streptococcus mutans
• 細胞内の位置: Secreted, cell wall; Peptidoglycan-anchor (Potential): P11657
• タンパク質・核酸の鎖数: 2
• 化学式量合計: 116459.18

構造登録者

Larson, M.R.,Rajashankar, K.R.,Crowley, P.J.,Kelly, C.,Mitchell, T.J.,Brady, L.J.,Deivanayagam, C. (登録日: 2011-01-19, 公開日: 2011-04-20, 最終更新日: 2024-11-06)

主引用文献

Larson, M.R.,Rajashankar, K.R.,Crowley, P.J.,Kelly, C.,Mitchell, T.J.,Brady, L.J.,Deivanayagam, C.
Crystal Structure of the C-terminal Region of Streptococcus mutans Antigen I/II and Characterization of Salivary Agglutinin Adherence Domains.
J.Biol.Chem., 286:21657-21666, 2011

PubMed Abstract: The Streptococcus mutans antigen I/II (AgI/II) is a cell surface-localized protein that adheres to salivary components and extracellular matrix molecules. Here we report the 2.5 Å resolution crystal structure of the complete C-terminal region of AgI/II. The C-terminal region is comprised of three major domains: C(1), C(2), and C(3). Each domain adopts a DE-variant IgG fold, with two β-sheets whose A and F strands are linked through an intramolecular isopeptide bond. The adherence of the C-terminal AgI/II fragments to the putative tooth surface receptor salivary agglutinin (SAG), as monitored by surface plasmon resonance, indicated that the minimal region of binding was contained within the first and second DE-variant-IgG domains (C(1) and C(2)) of the C terminus. The minimal C-terminal region that could inhibit S. mutans adherence to SAG was also confirmed to be within the C(1) and C(2) domains. Competition experiments demonstrated that the C- and N-terminal regions of AgI/II adhere to distinct sites on SAG. A cleft formed at the intersection between these C(1) and C(2) domains bound glucose molecules from the cryo-protectant solution, revealing a putative binding site for its highly glycosylated receptor SAG. Finally, electron microscopy images confirmed the elongated structure of AgI/II and enabled building a composite tertiary model that encompasses its two distinct binding regions.

PubMed: 21505225
DOI: 10.1074/jbc.M111.231100

実験手法

X-RAY DIFFRACTION (2.5 Å)