3AT7

Crystal structure of bacterial cell-surface alginate-binding protein Algp7

Summary for 3AT7

• Entry DOI: 10.2210/pdb3at7/pdb
• Descriptor: Alginate-binding flagellin (2 entities in total)
• Functional Keywords: two up-and-down four-helical bundles, alginate binding, alginate, structural protein
• Biological source: Sphingomonas
• Total number of polymer chains: 2
• Total formula weight: 63402.18

Authors

Maruyama, Y.,Ochiai, A.,Mikami, B.,Hashimoto, W.,Murata, K. (deposition date: 2010-12-27, release date: 2011-02-23, Last modification date: 2024-03-13)

Primary citation

Maruyama, Y.,Ochiai, A.,Mikami, B.,Hashimoto, W.,Murata, K.
Crystal structure of bacterial cell-surface alginate-binding protein with an M75 peptidase motif.
Biochem.Biophys.Res.Commun., 405:411-416, 2011

PubMed Abstract: A gram-negative Sphingomonas sp. A1 directly incorporates alginate polysaccharide into the cytoplasm via the cell-surface pit and ABC transporter. A cell-surface alginate-binding protein, Algp7, functions as a concentrator of the polysaccharide in the pit. Based on the primary structure and genetic organization in the bacterial genome, Algp7 was found to be homologous to an M75 peptidase motif-containing EfeO, a component of a ferrous ion transporter. Despite the presence of an M75 peptidase motif with high similarity, the Algp7 protein purified from recombinant Escherichia coli cells was inert on insulin B chain and N-benzoyl-Phe-Val-Arg-p-nitroanilide, both of which are substrates for a typical M75 peptidase, imelysin, from Pseudomonas aeruginosa. The X-ray crystallographic structure of Algp7 was determined at 2.10Å resolution by single-wavelength anomalous diffraction. Although a metal-binding motif, HxxE, conserved in zinc ion-dependent M75 peptidases is also found in Algp7, the crystal structure of Algp7 contains no metal even at the motif. The protein consists of two structurally similar up-and-down helical bundles as the basic scaffold. A deep cleft between the bundles is sufficiently large to accommodate macromolecules such as alginate polysaccharide. This is the first structural report on a bacterial cell-surface alginate-binding protein with an M75 peptidase motif.

PubMed: 21238429
DOI: 10.1016/j.bbrc.2011.01.043

Experimental method

X-RAY DIFFRACTION (2.1 Å)