期刊名称：Proceedings of the National Academy of Sciences
印刷版ISSN：0027-8424
电子版ISSN：1091-6490
出版年度：2008
卷号：105
期号：30
页码：10366-10371
DOI：10.1073/pnas.0800405105
语种：English
出版社：The National Academy of Sciences of the United States of America
摘要：This study has examined the atomic-level dynamics of the protein in the capsid of filamentous phage Pf1. This capsid consists of {approx}7,300 small subunits of only 46 aa in a helical array around a highly extended, circular single-stranded DNA molecule of 7,349 nt. Measurements were made of site-specific, solid-state NMR order parameters, [<]S[>], the values which are dimensionless quantities between 0 (mobile) and 1 (static) that characterize the amplitudes of molecular bond angular motions that are faster than microseconds. It was found that the protein subunit backbone is very static, and of particular interest, it appears to be static at residues glycine 15 and glutamine 16 where it had been previously thought to be mobile. In contrast to the backbone, several side chains display large-amplitude angular motions. Side chains on the virion exterior that interact with solvent are highly mobile, but surprisingly, the side chains of residues arginine 44 and lysine 45 near the DNA deep in the interior of the virion are also highly mobile. The large-amplitude dynamic motion of these positively charged side chains in their interactions with the DNA were not previously expected. The results reveal a highly dynamic aspect of a DNA-protein interface within a virus.
