Structural and kinetic analyses of macrophage migration inhibitory factor active site interactions.
Structural and kinetic analyses of macrophage migration inhibitory factor active site interactions.
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DOI：
10.1021/bi8014423
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发表时间：
2009-01-13
期刊：
影响因子：
2.9
通讯作者：
Lolis, Elias J.
中科院分区：
文献类型：
--
作者：
Crichlow, Gregg V.;Lubetsky, Jodi B.;Leng, Lin;Bucala, Richard;Lolis, Elias J.
巨噬细胞迁移抑制因子 (MIF) 是一种在多种细胞类型中表达的分泌蛋白，可对抗糖皮质激素的抗炎作用，并与败血症、癌症和某些自身免疫性疾病有关。有趣的是，MIF 的结构含有类似于微生物酶的互变异构酶/异构酶位点的催化位点。虽然真正的生理底物仍然未知，但模型底物已被识别。与互变异构酶活性位点结合的选定化合物也会抑制 MIF 的生物学功能。此前已有研究表明，对乙酰氨基酚代谢物 N-乙酰基-对苯醌亚胺 (NAPQI) 与 MIF 的活性位点共价结合。在这项研究中，动力学数据表明 NAPQI 可共价和非共价抑制 MIF。 MIF与NAPQI共结晶的结构表明，NAPQI发生了化学变化，形成对乙酰氨基酚二聚体（bi-APAP），并在活性位点口与MIF非共价结合。我们还发现常用的蛋白酶抑制剂苯甲基磺酰氟（PMSF）与MIF形成共价复合物并抑制互变异构酶活性。晶体分析表明，N 端脯氨酸的催化氮与 PMSF 的硫之间形成了稳定、新颖的 PMSF 共价键，在 MIF 同源三聚体的所有三个活性位点中具有完整、明确的电子密度。从这两种 MIF 抑制剂复合物的结构中得出了关于设计新化合物的结论，这些化合物可能提供更有效的 MIF 可逆和不可逆抑制。
Macrophage migration inhibitory factor (MIF) is a secreted protein expressed in numerous cell types that counters the anti-inflammatory effects of glucocorticoids and has been implicated in sepsis, cancer and certain auto-immune diseases. Interestingly, the structure of MIF contains a catalytic site resembling the tautomerase/isomerase sites of microbial enzymes. While bona fide physiological substrates remain unknown, model substrates have been identified. Selected compounds that bind in the tautomerase active site also inhibit biological functions of MIF. It had previously been shown that the acetaminophen metabolite, N-acetyl-p-benzoquinone imine (NAPQI), covalently binds to the active site of MIF. In this study, kinetic data indicate that NAPQI inhibits MIF both covalently and non-covalently. The structure of MIF co-crystallized with NAPQI reveals that the NAPQI has undergone a chemical alteration forming an acetaminophen dimer (bi-APAP), and binds non-covalently to MIF at the mouth of the active site. We also find that the commonly used protease inhibitor, phenylmethylsulfonyl fluoride (PMSF), forms a covalent complex with MIF and inhibits the tautomerase activity. Crystallographic analysis reveals the formation of a stable, novel covalent bond for PMSF between the catalytic nitrogen of the N-terminal proline and the sulfur of PMSF with complete, well-defined electron density in all three active sites of the MIF homotrimer. Conclusions are drawn from the structures of these two MIF-inhibitor complexes regarding the design of novel compounds that may provide more potent reversible and irreversible inhibition of MIF.
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DOI：
10.1107/s0907444904019158
发表时间：
2004-12-01
影响因子：
2.2
作者：
Emsley, P;Cowtan, K
通讯作者：
Cowtan, K
影响因子：
2.9
作者：
JAMES, GT
通讯作者：
JAMES, GT
影响因子：
7.3
作者：
Dios, A;Mitchell, RA;Al-Abed, Y
通讯作者：
Al-Abed, Y
DOI：
10.1107/s0907444998003254
发表时间：
1998-09-01
期刊：
ACTA CRYSTALLOGRAPHICA SECTION D-BIOLOGICAL CRYSTALLOGRAPHY
影响因子：
--
作者：
Brunger, AT;Adams, PD;Warren, GL
通讯作者：
Warren, GL
影响因子：
4.8
作者：
Crichlow, Gregg V.;Cheng, Kai Fan;Al-Abed, Yousef
通讯作者：
Al-Abed, Yousef