Solution Structure and Functional Ligand Screening of HI0719, a Highly Conserved Protein from Bacteria to Humans in the YjgF/YER057c/UK114 Family

详细信息    查看全文

• 作者：Lisa Parsons ; Nicklas Bonander ; Edward Eisenstein ; Michael Gilson ; Visvaldas Kairys ; and John Orban
• 刊名：Biochemistry
• 出版年：2003
• 出版时间：January 14, 2003
• 年：2003
• 卷：42
• 期：1
• 页码：80 - 89
• 全文大小：834K
• 年卷期：v.42,no.1(January 14, 2003)
• ISSN：1520-4995

文摘

HI0719 belongs to a large family of highly conserved proteins with no definitive molecularfunction and is found in organisms ranging from bacteria to humans. We describe the NMR structure ofHI0719, the first solution structure for a member of this family. The overall fold is similar to the crystalstructures of two homologues, YabJ from Bacillus subtilis and YjgF from Escherichia coli, and all threestructures are similar to that of chorismate mutase, although there is little sequence homology and noapparent functional connection. HI0719 is a homotrimer with a distinct cavity located at the subunitinterface. Six of the seven invariant residues in the high identity group of proteins are located in thiscavity, suggesting that this may be a binding site for small molecules. Using previously publishedobservations about the biological role of HI0719 family members as a guide, over 100 naturally occurringsmall molecules or structural analogues were screened for ligand binding using NMR spectroscopy. Thetargeted screening approach identified six compounds that bind to HI0719 at the putative active site. Fiveof these compounds are either mages/gifchars/alpha.gif" BORDER=0>-keto acids or mages/gifchars/alpha.gif" BORDER=0>,mages/gifchars/beta2.gif" BORDER=0 ALIGN="middle">-unsaturated acids, while the sixth compound is structurallysimilar. Previous studies have proposed that some HI0719 homologues may act on small molecules in theisoleucine biosynthetic path and, if this is correct, the ligand screening results presented here suggest thatthe interaction most likely occurs with 2-ketobutyrate and/or its unstable enamine precursor.