Alkalimonas amylolytica N10是中科院微生物所马延和研究员课题组筛选自内蒙古盐碱湖中的一株嗜碱菌新种，为革兰氏阴性菌。该菌能够在pH8.0-11.0的碱性环境中生存，其最适生长的环境pH约为9.5。目前对于嗜碱菌的嗜碱机理尚不完全清楚，研究领域也主要集中在革兰氏阳性嗜碱菌的某个或某一类蛋白，而未考虑生物体可能是通过一种蛋白协同网络效应的方式来进行的。
该研究通过对嗜碱菌N10在不同pH环境中生长时的膜蛋白质组和胞浆蛋白质组对环境的应答情况进行了系统的研究，结果表明能量代谢相关蛋白、质子转运蛋白等在不同碱性的环境中发生了显著的差异变化，这可能与嗜碱菌N10的嗜碱机制相关。该研究成果发表在《蛋白质组学》（Proteomics）第九卷上，为从全局角度阐释嗜碱菌的嗜碱机理提供了重要参考。（生物谷Bioon.com）
生物谷推荐原始出处：
Proteomics，doi:10.1002/pmic.200800244 ，Quanhui Wang ，Yanhe Ma
Exploring membrane and cytoplasm proteomic responses of Alkalimonas amylolytica N10 to different external pHs with combination strategy of de novo peptide sequencing
Quanhui Wang 1, Huiming Han 1, Yanfen Xue 1, Zhong Qian 2 3, Bo Meng 2 3, Fuli Peng 2 3, Zhuowei Wang 2 3, Wei Tong 2 3, Chuanqi Zhou 2 3, Qian Wang 2 3, Yonghao Guo 1, Gang Li 1, Siqi Liu, Dr. 2 3, Yanhe Ma, Dr. 1 *
1State Key Laboratory of Microbial Resources, Institute of Microbiology, Chinese Academy of Sciences, Beijing, P. R. China
2Center of Proteomic Analysis, Beijing Genomics Institute, Chinese Academy of Sciences, Beijing, P. R. China
3Beijing Proteomics Institute, Shunyi, Beijing, P. R. China
*Correspondence to Yanhe Ma, State Key Laboratory of Microbial Resources, Institute of Microbiology, Chinese Academy of Sciences, Beijing 100101, P. R. China
ABSTRACT
Identification of differentially proteomic responses to external pHs would pave an access for understanding of survival mechanisms of bacteria living at extreme pH environment. We cultured Alkalimonas amylolytica N10 (N10), a novel alkaliphilic bacterium found in Lake Chahannor, in media with three different pHs and extracted the correspondent membrane and cytoplasm proteins for proteomic analysis through 2-DE. The differential 2-DE spots corresponding to the altered pHs were delivered to MALDI TOF/TOF MS for protein identification. Since the genomic data of strain N10 was unavailable, we encountered a problem at low rate of protein identification with 18.1%. We employed, therefore, a combined strategy of de novo sequencing to analyze MS/MS signals generated from MALDI TOF/TOF MS. A significantly improved rate of protein identification was thus achieved at over than 70.0%. Furthermore, we extensively investigated the expression of these pH-dependent N10 genes using Western blot and real-time PCR. The conclusions drawn from immunoblot and mRNA measurements were mostly in agreement with the proteomic observations. We conducted the bioinformatic analysis to all the pH-dependent N10 proteins and found that some membrane proteins participated in iron transport were differentially expressed as external pH elevated and most of differential proteins with increased or bell-shape mode of pH-dependence were involved in bioenergetic process and metabolism of carbohydrates, fatty acid, amino acids, and nucleotides. Our data thus provide a functional profile of the pH-responsive proteins in alkaliphiles, leading to elucidation of alkaliphilic-adaptive mechanism.
