Wang Yingchun, Xu Wu, Chitnis Parag R
Department of Biochemistry, Biophysics and Molecular Biology, Iowa State University, Ames, 50011, USA.
Proteome Sci. 2009 Mar 25;7:11. doi: 10.1186/1477-5956-7-11.
The membranes of Synechocystis sp. PCC 6803 play a central role in photosynthesis, respiration and other important metabolic pathways. Comprehensive identification of the membrane proteins is of importance for a better understanding of the diverse functions of its unique membrane structures. Up to date, approximately 900 known or predicted membrane proteins, consisting 24.5% of Synechocystis sp. PCC 6803 proteome, have been indentified by large-scale proteomic studies.
To resolve more membrane proteins on 2-D gels for mass spectrometry identification, we separated integral proteins from membrane associated proteins and collected them as the integral and peripheral fractions, respectively. In total, 95 proteins in the peripheral fraction and 29 proteins in the integral fraction were identified, including the 5 unique proteins that were not identified by any previous studies. Bioinformatic analysis revealed that the identified proteins can be functionally classified into 14 distinct groups according to the cellular functions annotated by Cyanobase, including the two largest groups hypothetical and unknown, and photosynthesis and respiration. Homology analysis indicates that the identified membrane proteins are more conserved than the rest of the proteome.
The proteins identified in this study combined with other published proteomic data provide the most comprehensive Synechocystis proteome catalog, which will serve as a useful reference for further detailed studies to address protein functions through both traditional gene-by-gene and systems biology approaches.
集胞藻PCC 6803的膜在光合作用、呼吸作用及其他重要代谢途径中发挥核心作用。全面鉴定膜蛋白对于更好地理解其独特膜结构的多样功能至关重要。到目前为止,通过大规模蛋白质组学研究已鉴定出约900种已知或预测的膜蛋白,占集胞藻PCC 6803蛋白质组的24.5%。
为了在二维凝胶上分离更多膜蛋白用于质谱鉴定,我们将整合蛋白与膜相关蛋白分离,并分别将它们收集为整合部分和外周部分。总共鉴定出外周部分中的95种蛋白和整合部分中的29种蛋白,包括5种以前任何研究都未鉴定出的独特蛋白。生物信息学分析表明,根据蓝藻数据库注释的细胞功能,鉴定出的蛋白可在功能上分为14个不同的组,包括最大的两组,即假定的和未知的,以及光合作用和呼吸作用相关的组。同源性分析表明,鉴定出的膜蛋白比蛋白质组的其他部分更保守。
本研究中鉴定出的蛋白与其他已发表的蛋白质组学数据相结合,提供了最全面的集胞藻蛋白质组目录,这将为通过传统的逐个基因和系统生物学方法进一步详细研究蛋白功能提供有用的参考。