Structural studies of human placental alkaline phosphatase in complex with functional ligands

被引:81
作者
Llinas, P
Stura, EA
Ménez, A
Kiss, Z
Stigbrand, T
Millán, JL
Le Du, MH [1 ]
机构
[1] CEA, Lab Struct Prot, Dept Ingn & Etud Prot, F-91191 Gif Sur Yvette, France
[2] Univ Minnesota, Hormel Inst, Austin, MN 55912 USA
[3] Umea Univ, Dept Med Biosci Med Genet, S-90185 Umea, Sweden
[4] Burnham Inst, La Jolla, CA 92037 USA
[5] Umea Univ, Dept Immunol, S-90185 Umea, Sweden
关键词
placental alkaline phosphatase; peripheral site; catalytic site selectivity; human alkaline phosphatase isozymes;
D O I
10.1016/j.jmb.2005.04.068
中图分类号
Q5 [生物化学]; Q7 [分子生物学];
学科分类号
071010 ; 081704 ;
摘要
The activity of human placental alkaline phosphatase (PLAP) is down-regulated by a number of effectors such as L-phenylalanine, an uncompetitive inhibitor, 5'-AMP, an antagonist of the effects of PLAP on fibroblast proliferation and by p-nitrophenyl-phosphonate (PNPPate), a nonhydrolysable substrate analogue. For the first two, such regulation may be linked to its biological function that requires a reduced and better-regulated hydrolytic rate. To understand how such disparate ligands are able to inhibit the enzyme, we solved the structure of the complexes at 1.6 angstrom, 1.9 angstrom and 1.9 angstrom resolution, respectively. These crystal structures are the first of an alkaline phosphatase in complex with organic inhibitors. Of the three inhibitors, only L-Phe and PNPPate bind at the active site hydrophobic pocket, providing structural data on the uncompetitive inhibition process. In contrast, all three ligands interact at a remote peripheral site located 28 A from the active site. In order to extend these observations to the other members of the human alkaline phosphatase family, we have modelled the structures of the other human isozymes and compared them to PLAP. This comparison highlights the crucial role played by position 429 at the active site in the modulation of the catalytic process, and suggests that the peripheral binding site may be involved in the functional specialization of the PLAP isozyme. (c) 2005 Elsevier Ltd. All rights reserved.
引用
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页码:441 / 451
页数:11
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