Proteomic Analysis of an Unculturable Bacterial Endosymbiont (Blochmannia) Reveals High Abundance of Chaperonins and Biosynthetic Enzymes

详细信息    查看全文

• 作者：Yongliang Fan ; J. Will Thompson ; Laura G. Dubois ; M. Arthur Moseley ; Jennifer J. Wernegreen
• 刊名：Journal of Proteome Research
• 出版年：2013
• 出版时间：February 1, 2013
• 年：2013
• 卷：12
• 期：2
• 页码：704-718
• 全文大小：622K
• 年卷期：v.12,no.2(February 1, 2013)
• ISSN：1535-3907

文摘

Many insect groups have coevolved with bacterial endosymbionts that live within specialized host cells. As a salient example, ants in the tribe Camponotini rely on Blochmannia, an intracellular bacterial mutualist that synthesizes amino acids and recycles nitrogen for the host. We performed a shotgun, label-free, LC/MS/MS quantitative proteomic analysis to investigate the proteome of Blochmannia associated with Camponotus chromaiodes. We identified more than 330 Blochmannia proteins, or 54% coverage of the predicted proteome, as well as 244 Camponotus proteins. Using the average intensity of the top 3 鈥渂est flier鈥?peptides along with spiking of a surrogate standard at a known concentration, we estimated the concentration (fmol/渭g) of those proteins with confident identification. The estimated dynamic range of Blochmannia protein abundance spanned 3 orders of magnitude and covered diverse functional categories, with particularly high representation of metabolism, information transfer, and chaperones. GroEL, the most abundant protein, totaled 6% of Blochmannia protein abundance. Biosynthesis of essential amino acids, fatty acids, and nucleotides, and sulfate assimilation had disproportionately high coverage in the proteome, further supporting a nutritional role of the symbiosis. This first quantitative proteomic analysis of an ant endosymbiont illustrates a promising approach to study the functional basis of intimate symbioses.

Keywords:

quantitative proteomics; high definition mass spectrometry; MS^E; HDMS^E; endosymbiosis; uncultivable bacteria; Camponotus; Blochmannia; GroEL