4MNP

Structure of the Sialic Acid Binding Protein from Fusobacterium Nucleatum subsp. nucleatum ATCC 25586

Summary for 4MNP

• Entry DOI: 10.2210/pdb4mnp/pdb
• Related: 3B50 4MAG 4MMP
• Descriptor: N-acetylneuraminate-binding protein, N-acetyl-beta-neuraminic acid (3 entities in total)
• Functional Keywords: sugar binding protein, sialic acid binding protein, sialic acid
• Biological source: Fusobacterium nucleatum subsp. nucleatum
• Total number of polymer chains: 1
• Total formula weight: 35681.91

Authors

Thanuja, G.,Ramaswamy, S. (deposition date: 2013-09-11, release date: 2014-07-09, Last modification date: 2023-09-20)

Primary citation

Gangi Setty, T.,Cho, C.,Govindappa, S.,Apicella, M.A.,Ramaswamy, S.
Bacterial periplasmic sialic acid-binding proteins exhibit a conserved binding site.
Acta Crystallogr.,Sect.D, 70:1801-1811, 2014

PubMed Abstract: Sialic acids are a family of related nine-carbon sugar acids that play important roles in both eukaryotes and prokaryotes. These sialic acids are incorporated/decorated onto lipooligosaccharides as terminal sugars in multiple bacteria to evade the host immune system. Many pathogenic bacteria scavenge sialic acids from their host and use them for molecular mimicry. The first step of this process is the transport of sialic acid to the cytoplasm, which often takes place using a tripartite ATP-independent transport system consisting of a periplasmic binding protein and a membrane transporter. In this paper, the structural characterization of periplasmic binding proteins from the pathogenic bacteria Fusobacterium nucleatum, Pasteurella multocida and Vibrio cholerae and their thermodynamic characterization are reported. The binding affinities of several mutations in the Neu5Ac binding site of the Haemophilus influenzae protein are also reported. The structure and the thermodynamics of the binding of sugars suggest that all of these proteins have a very well conserved binding pocket and similar binding affinities. A significant conformational change occurs when these proteins bind the sugar. While the C1 carboxylate has been identified as the primary binding site, a second conserved hydrogen-bonding network is involved in the initiation and stabilization of the conformational states.

PubMed: 25004958
DOI: 10.1107/S139900471400830X

Experimental method

X-RAY DIFFRACTION (2.5 Å)