The Structure of PTP-1B in Complex with a Peptide Inhibitor Reveals an Alternative Binding Mode for Bisphosphonates

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• 作者：Ernest Asante-Appiah ; Sangita Patel ; Claude Dufresne ; Patrick Roy ; Qingping Wang ; Vira Patel ; Richard W. Friesen ; Chidambaram Ramachandran ; Joseph W. Becker ; Yves Leblanc ; Brian P. Kennedy ; and Giovan
• 刊名：Biochemistry
• 出版年：2002
• 出版时间：July 23, 2002
• 年：2002
• 卷：41
• 期：29
• 页码：9043 - 9051
• 全文大小：377K
• 年卷期：v.41,no.29(July 23, 2002)
• ISSN：1520-4995

文摘

Inhibitors of PTP-1B could be therapeutically beneficial in the treatment of type 2 diabetes.Owing to the large number of phosphatases in the cell, inhibitors against PTP-1B must not only be potentbut selective as well. N-Benzoyl-L-glutamyl-[4-phosphono(difluoromethyl)]-L-phenylalanine-[4-phosphono(difluoro-methyl)]-L-phenylalanineamide (BzN-EJJ-amide) is a low nanomolar inhibitor of PTP-1B thatshows selectivity over several protein tyrosine phosphatases. To gain an insight into the basis of its potencyand selectivity, we evaluated several analogues of the inhibitor and introduced amino acid substitutionsinto PTP-1B by site-directed mutagenesis. We also determined the crystal structure of PTP-1B in complexwith BzN-EJJ-amide at 2.5 Å resolution. Our results indicate that the high inhibitory potency is due tointeractions of several of its chemical groups with specific protein residues. An interaction between BzN-EJJ-amide and Asp48 is of particular significance, as substitution of Asp48 to alanine resulted in a100-fold loss in potency. The crystal structure also revealed an unexpected binding orientation for abisphosphonate inhibitor on PTP-1B, where the second difluorophosphonomethyl phenylalanine (F₂PMP)moiety is bound close to Arg47 rather than in the previously identified second aryl phosphate site demarkedby Arg24 and Arg254. Our results suggest that potent and selective PTP-1B inhibitors may be designedby targeting the region containing Arg47 and Asp48.