3GA5

X-ray structure of glucose/galactose receptor from Salmonella typhimurium in complex with (2R)-glyceryl-beta-D-galactopyranoside

Summary for 3GA5

• Entry DOI: 10.2210/pdb3ga5/pdb
• Related: 1GCA 1GCG 3GBP
• Descriptor: D-galactose-binding periplasmic protein, (2R)-2,3-dihydroxypropyl beta-D-galactopyranoside, CALCIUM ION, ... (6 entities in total)
• Functional Keywords: glucose/galactose binding protein, glyceryl galactoside, salmonella enterica serovar typhimurium, calcium, chemotaxis, periplasm, sugar transport, transport, sugar binding protein
• Biological source: Salmonella typhimurium
• Cellular location: Periplasm: P23905
• Total number of polymer chains: 2
• Total formula weight: 67614.01

Authors

Sooriyaarachchi, S.,Ubhayasekera, W.,Mowbray, S.L. (deposition date: 2009-02-16, release date: 2009-04-14, Last modification date: 2023-11-01)

Primary citation

Sooriyaarachchi, S.,Ubhayasekera, W.,Boos, W.,Mowbray, S.L.
X-ray structure of glucose/galactose receptor from Salmonella typhimurium in complex with the physiological ligand, (2R)-glyceryl-beta-D-galactopyranoside
Febs J., 276:2116-2124, 2009

PubMed Abstract: Periplasmic binding proteins are abundant in bacteria by virtue of their essential roles as high-affinity receptors in ABC transport systems and chemotaxis. One of the best studied of these receptors is the so-called glucose/galactose-binding protein. Here, we report the X-ray structure of the Salmonella typhimurium protein bound to the physiologically relevant ligand, (2R)-glyceryl-beta-D-galactopyranoside, solved by molecular replacement, and refined to 1.87 A resolution with R and R-free values of 17% and 22%. The structure identifies three amino acid residues that are diagnostic of (2R)-glyceryl-beta-D-galactopyranoside binding (Thr110, Asp154 and Gln261), as opposed to binding to the monosaccharides glucose and galactose. These three residues are conserved in essentially all available glucose/galactose-binding protein sequences, indicating that the binding of (2R)-glyceryl-beta-D-galactopyranoside is the rule rather than the exception for receptors of this type. The role of (2R)-glyceryl-beta-D-galactopyranoside in bacterial biology is discussed. Further, comparison of the available structures provides the most complete description of the conformational changes of glucose/galactose-binding protein to date. The structures follow a smooth and continuous path from the most closed structure [that bound to (2R)-glyceryl-beta-D-galactopyranoside] to the most open (an apo structure).

PubMed: 19292879
DOI: 10.1111/j.1742-4658.2009.06945.x

Experimental method

X-RAY DIFFRACTION (1.87 Å)