Structure of an ABC transporter solute-binding protein specific for the amino sugars glucosamine and galactosamine

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• 作者：Umesh Yadava ; Matthew W. Vetting ; Nawar Al Obaidi ; Michael S. Carter ; John A. Gerlt and Steven C. Almo
• 关键词：solute-binding protein ; differential scanning fluorimetry ; Thermofluor ; Agrobacterium vitis ; Avi_5305 ; Pfam13407
• 刊名：Acta Crystallographica Section F
• 出版年：2016
• 出版时间：June 2016
• 年：2016
• 卷：72
• 期：6
• 页码：467-472
• 全文大小：631K
• ISSN：1744-3091

文摘

The uptake of exogenous solutes by prokaryotes is mediated by transport systems embedded in the plasma membrane. In many cases, a solute-binding protein (SBP) is utilized to bind ligands with high affinity and deliver them to the membrane-bound components responsible for translocation into the cytoplasm. In the present study, Avi_5305, an Agrobacterium vitis SBP belonging to Pfam13407, was screened by differential scanning fluorimetry (DSF) and found to be stabilized by an class="smallCaps">dan>-glucosamine and an class="smallCaps">dan>-galactosamine. Avi_5305 is the first protein from Pfam13407 shown to be specific for amino sugars, and co-crystallization resulted in structures of Avi_5305 bound to an class="smallCaps">dan>-glucosamine and an class="smallCaps">dan>-galactosamine. Typical of Pfam13407, Avi_5305 consists of two α/β domains linked through a hinge region, with the ligand-binding site located in a cleft between the two domains. Comparisons with Escherichia coli ribose-binding protein suggest that a cation–π interaction with Tyr168 provides the specificity for an class="smallCaps">dan>-glucosamine/an class="smallCaps">dan>-galactosamine over an class="smallCaps">dan>-glucose/an class="smallCaps">dan>-galactose.