کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
1924775 | 1536307 | 2016 | 10 صفحه PDF | دانلود رایگان |
عنوان انگلیسی مقاله ISI
Mutagenic and chemical analyses provide new insight into enzyme activation and mechanism of the type 2 iron-sulfur l-serine dehydratase from Legionella pneumophila
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کلمات کلیدی
CHESl-serine dehydratased-serine dehydrataseN-cyclohexyl-2-aminoethanesulfonic acidTRISMOPSACTDSDLSD3-(N-morpholino)propanesulfonic acid - 3- (N-مورفولینو) پروپان سولفونیک اسیدl-Serine - L-Serineiron-sulfur - آهن گوگردTris(hydroxymethyl)aminomethane - تریس (هیدروکسی متیل) آمینومتانDehydratase - دهیدراتازASB - لطفاlysogeny broth - لیزوزومی گوگردLTD - محدودMeS - مس
موضوعات مرتبط
علوم زیستی و بیوفناوری
بیوشیمی، ژنتیک و زیست شناسی مولکولی
زیست شیمی
پیش نمایش صفحه اول مقاله
چکیده انگلیسی
The crystal structure of the Type 2Â l-serine dehydratase from Legionella pneumophila (lpLSD), revealed a “tail-in-mouth” configuration where the C-terminal residue acts as an intrinsic competitive inhibitor. This pre-catalytic structure undergoes an activation step prior to catalytic turnover. Mutagenic analysis of residues at or near the active site cleft is consistent with stabilization of substrate binding by many of the same residues that interact with the C-terminal cysteine and highlight the critical role of certain tail residues in activity. pH-rate profiles show that a residue with pK of 5.9 must be deprotonated and a residue with a pK of 8.5 must be protonated for activity. This supports an earlier suggestion that His 61 is the likely catalytic base. An additional residue with a pK of 8.5-9 increases cooperativity when it is deprotonated. This investigation also demonstrates that the Fe-S dehydratases convert the enamine/imine intermediates of the catalytic reaction to products on the enzyme prior to release. This is in contrast to pyridoxyl 5â² phosphate based dehydratases that release an enamine/imine intermediate into solution, which then hydrolyzes to produce the ketoamine product.
ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Archives of Biochemistry and Biophysics - Volume 596, 15 April 2016, Pages 108-117
Journal: Archives of Biochemistry and Biophysics - Volume 596, 15 April 2016, Pages 108-117
نویسندگان
Xiao Lan Xu, Gregory A. Grant,