1QSA

CRYSTAL STRUCTURE OF THE 70 KDA SOLUBLE LYTIC TRANSGLYCOSYLASE SLT70 FROM ESCHERICHIA COLI AT 1.65 ANGSTROMS RESOLUTION

1QSA の概要

• エントリーDOI: 10.2210/pdb1qsa/pdb
• 関連するPDBエントリー: 1QTE 1SLY
• 分子名称: PROTEIN (SOLUBLE LYTIC TRANSGLYCOSYLASE SLT70), SULFATE ION, ACETATE ION, ... (5 entities in total)
• 機能のキーワード: alpha-superhelix, transferase
• 由来する生物種: Escherichia coli
• 細胞内の位置: Periplasm: P03810
• タンパク質・核酸の鎖数: 1
• 化学式量合計: 72497.04

構造登録者

van Asselt, E.J.,Thunnissen, A.-M.W.H.,Dijkstra, B.W. (登録日: 1999-06-20, 公開日: 1999-09-01, 最終更新日: 2024-11-06)

主引用文献

van Asselt, E.J.,Thunnissen, A.M.,Dijkstra, B.W.
High resolution crystal structures of the Escherichia coli lytic transglycosylase Slt70 and its complex with a peptidoglycan fragment.
J.Mol.Biol., 291:877-898, 1999

PubMed Abstract: The 70 kDa soluble lytic transglycosylase (Slt70) from Escherichia coli is an exo-muramidase, that catalyses the cleavage of the glycosidic bonds between N -acetylmuramic acid and N -acetylglucosamine residues in peptidoglycan, the main structural component of the bacterial cell wall. This cleavage is accompanied by the formation of a 1,6-anhydro bond between the C1 and O6 atoms in the N -acetylmuramic acid residue (anhMurNAc). Crystallographic studies at medium resolution revealed that Slt70 is a multi-domain protein consisting of a large ring-shaped alpha-superhelix with on top a catalytic domain, which resembles the fold of goose-type lysozyme. Here we report the crystal structures of native Slt70 and of its complex with a 1,6-anhydromuropeptide solved at nominal resolutions of 1.65 A and 1.90 A, respectively. The high resolution native structure reveals the details on the hydrogen bonds, electrostatic and hydrophobic interactions that stabilise the catalytic domain and the alpha-superhelix. The building-block of the alpha-superhelix is an "up-down-up-down" four-alpha-helix bundle involving both parallel and antiparallel helix pairs. Stabilisation of the fold is provided through an extensive packing of apolar atoms, mostly from leucine and alanine residues. It lacks, however, an internal consensus sequence that characterises other super-secondary helical folds like the beta-helix in pectate lyase or the (beta-alpha)-helix in the ribonuclease inhibitor. The 1, 6-anhydromuropeptide product binds in a shallow groove adjacent to the peptidoglycan-binding groove of the catalytic domain. The groove is formed by conserved residues at the interface of the catalytic domain and the alpha-superhelix. The structure of the Slt70-1, 6-anhydromuropeptide complex confirms the presence of a specific binding-site for the peptide moieties of the peptidoglycan and it substantiates the notion that Slt70 starts the cleavage reaction at the anhMurNAc end of the peptidoglycan.

PubMed: 10452894
DOI: 10.1006/jmbi.1999.3013

実験手法

X-RAY DIFFRACTION (1.65 Å)