Structural proteomics of an archaeon

A set of 424 nonmembrane proteins from Methanobacterium thermoautotrophicum were cloned, expressed and purified for structural studies. Of these, simi lar to 20% were found to be suitable candidates for X-ray crystallographic or NMR spectroscopic analysis without further optimization of conditions, p roviding an estimate of the number of the most accessible structural target s in the proteome. A retrospective analysis of the experimental behavior of these proteins suggested some simple relations between sequence and solubi lity. implying that data bases of protein properties will be useful in opti mizing high throughput strategies. Of the first 10 structures determined, s everal provided clues to biochemical functions that were not detectable fro m sequence analysis, and in many cases these putative functions could be re adily confirmed by biochemical methods. This demonstrates that structural p roteomics is feasible and can play a central role in functional genomics,