证据表明,辅酶ii +生理代数余子式的ADP-L-glycero-D-mannoheptose 6-epimerase。
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倪Y, McPhie P,执事,Ealick年代,科尔曼WG Jr
证据表明,辅酶ii +生理代数余子式的ADP-L-glycero-D-mannoheptose 6-epimerase。
生物化学杂志。2001年7月20日;276 (29):27329 - 34。Epub 2001年4月19日。
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11313358 (在PubMed]
- 文摘
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需要ADP-L-glycero-D-mannoheptose 6-epimerase脂多糖核心在几个属革兰氏阴性细菌的生物合成。酶既包含指纹序列Gly-X-Gly-X-X-Gly及其附近Gly-X-X-Gly-X-X-Gly N末端,是指示性的ADP绑定褶皱。先前的研究的ADP-l-glycero-D-mannoheptose 6-epimerase (ADP-hep 6-epimerase)与NAD(+)代数余子式是一致的。然而,晶体结构的ADP-hep 6-epimerase显示绑定辅酶ii(执事,a . M。、镍、y S。科尔曼,w·G。,Jr .)和Ealick s e . 5(2000)结构,453 - 462)。在目前的研究中,apo-ADP-hep 6-epimerase与NAD(+)重组,辅酶ii(+),和时尚。在这个报告中我们提供数据显示NAD(+)和NADP(+)还原酶活性恢复,但时尚不能。此外,ADP-hep 6-epimerase表现出偏爱绑定的辅酶ii在NAD (+) (+)。辅酶ii的K (d)值(+)是26 microm而45 microm NAD (+)。 Ultraviolet circular dichroism spectra showed that apo-ADP-hep 6-epimerase reconstituted with NADP(+) had more secondary structure than apo-ADP-hep 6-epimerase reconstituted with NAD(+). Perchloric acid extracts of the purified enzyme were assayed with NAD(+)-specific alcohol dehydrogenase and NADP(+)-specific isocitric dehydrogenase. A sample of the same perchloric acid extract was analyzed in chromatographic studies, which demonstrated that ADP-hep 6-epimerase binds NADP(+) in vivo. A structural comparison of ADP-hep 6-epimerase with UDP-galactose 4-epimerase, which utilizes an NAD(+) cofactor, has identified the regions of ADP-hep 6-epimerase, which defines its specificity for NADP(+).