کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
7560236 | 1491439 | 2018 | 44 صفحه PDF | دانلود رایگان |
عنوان انگلیسی مقاله ISI
Similar structural stabilities of 3-isopropylmalate dehydrogenases from the obligatory piezophilic bacterium Shewanella benthica strain DB21MT-2 and its atmospheric congener S. oneidensis strain MR-1
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کلمات کلیدی
IPMPAGECSMUrea-induced unfolding3-isopropylmalate dehydrogenaseIPMDHdhfr - DhfrUltraviolet - اشعه فرابنفشpolyacrylamide gel electrophoresis - الکتروفورز ژل پلی آکریل آمیدoxidized nicotinamide adenine dinucleotide - اکسید نیکوتین آمید آدنین دینکلوتیدvolume change - تغییر حجمStructural stability - ثبات ساختاریdihydrofolate reductase - دی هیدروفلات ردوکتازcircular dichroism - رنگ تابی دورانیNAD - نادانIsoelectric point - نقطه ایزوالکتریک
موضوعات مرتبط
مهندسی و علوم پایه
شیمی
شیمی آنالیزی یا شیمی تجزیه
پیش نمایش صفحه اول مقاله
چکیده انگلیسی
We previously found that the enzymatic activity of 3-isopropylmalate dehydrogenase from the obligatory piezophilic bacterium Shewanella benthica strain DB21MT-2 (SbIPMDH) was pressure-tolerant up to 100â¯MPa, but that from its atmospheric congener S. oneidensis strain MR-1 (SoIPMDH) was pressure-sensitive. Such characteristics were determined by only one amino acid residue at position 266, serine (SoIPMDH) or alanine (SbIPMDH) [Y. Hamajima et al. Extremophiles 20: 177, 2016]. In this study, we investigated the structural stability of these enzymes. At pHâ¯7.6, SoIPMDH was slightly more stable against hydrostatic pressure than SbIPMDH, contrary to the physiological pressures of their normal environments. Pressure unfolding of these IPMDHs followed a two-state unfolding model between a native dimer and two unfolded monomers, and the dimer structure was pressure-tolerant up to 200â¯MPa, employing a midpoint pressure of 245.3â¯Â±â¯0.1â¯MPa and a volume change of â225â¯Â±â¯24â¯mLâ¯molâ1 for the most unstable mutant, SbIPMDH A266S. Thus, their pressure-dependent activity did not originate from structural perturbations such as unfolding or dimer dissociation. Conversely, urea-induced unfolding of these IPMDHs followed a three-state unfolding model, including a dimer intermediate. Interestingly, the first transition was strongly pH-dependent but pressure-independent; however, the second transition showed the opposite pattern. Obtained volume changes due to urea-induced unfolding were almost equal for both IPMDHs, approximately +10 andâ¯â30â¯mLâ¯molâ1 for intermediate formation and dimer dissociation, respectively. These results indicated that both IPMDHs have similar structural stability, and a pressure-adaptation mechanism was provided for only the enzymatic activity of SbIPMDH.
ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Biochimica et Biophysica Acta (BBA) - Proteins and Proteomics - Volume 1866, Issues 5â6, MayâJune 2018, Pages 680-691
Journal: Biochimica et Biophysica Acta (BBA) - Proteins and Proteomics - Volume 1866, Issues 5â6, MayâJune 2018, Pages 680-691
نویسندگان
Eiji Ohmae, Yuki Hamajima, Takayuki Nagae, Nobuhisa Watanabe, Chiaki Kato,