Department of Microbiology, University of Delhi, South Campus, New Delhi 110021, India.
Bioresour Technol. 2012 Sep;120:314-7. doi: 10.1016/j.biortech.2012.06.038. Epub 2012 Jun 22.
Recombinant Escherichia coli HB101 harboring keratinase rKP2 from Pseudomonas aeruginosa KS-1 degraded 2% chicken feather in LB-Amp medium in 24h. SEM analysis and detailed studies revealed that bacterial colonization of feather was a pre-requisite for degradation of feather by keratinase. The mechanism of sulfitolysis revealed involvement of free cystinyl group as a source of redox during colonization as DTNB inhibited feather degradation by rKP2. Involvement of GGT-GSH system in contribution of free cystinyl group for redox was established by using GGT knockout recombinant E. coli strain that failed to degrade feather inspite of successful colonization and keratinase production. Short term experiments further confirmed enhanced protein release from feather keratin in presence of GGT-GSH redox. In the presence of similar redox, rKP2 also degraded surrogate prion protein, Sup 35NM in 15 min at 37°C, pH 7.0.
重组大肠杆菌 HB101 中含有来自铜绿假单胞菌 KS-1 的角蛋白酶 rKP2，可在 24 小时内将 2%的鸡毛降解在 LB-Amp 培养基中。扫描电镜分析和详细研究表明，细菌对羽毛的定殖是角蛋白酶降解羽毛的前提条件。巯基分解作用的机制表明，游离半胱氨酰基作为氧化还原过程中的来源参与其中，因为 DTNB 抑制 rKP2 对角蛋白酶的降解。使用 GGT 敲除重组大肠杆菌菌株，发现 GGT-GSH 系统参与了游离半胱氨酰基的氧化还原贡献，该菌株尽管成功定殖并产生角蛋白酶，但未能降解羽毛。短期实验进一步证实了在 GGT-GSH 氧化还原存在的情况下，从羽毛角蛋白中释放出更多的蛋白质。在类似的氧化还原条件下，rKP2 还能在 37°C、pH7.0 下在 15 分钟内降解替代朊病毒蛋白 Sup35NM。
