| Literature DB >> 24836025 |
Alessandro A Rizzo1, Margaret M Suhanovsky1, Matthew L Baker2, LaTasha C R Fraser1, Lisa M Jones3, Don L Rempel3, Michael L Gross3, Wah Chiu2, Andrei T Alexandrescu4, Carolyn M Teschke5.
Abstract
Some capsid proteins built on the ubiquitous HK97-fold have accessory domains imparting specific functions. Bacteriophage P22 coat protein has a unique insertion domain (I-domain). Two prior I-domain models from subnanometer cryoelectron microscopy (cryoEM) reconstructions differed substantially. Therefore, the I-domain's nuclear magnetic resonance structure was determined and also used to improve cryoEM models of coat protein. The I-domain has an antiparallel six-stranded β-barrel fold, not previously observed in HK97-fold accessory domains. The D-loop, which is dynamic in the isolated I-domain and intact monomeric coat protein, forms stabilizing salt bridges between adjacent capsomers in procapsids. The S-loop is important for capsid size determination, likely through intrasubunit interactions. Ten of 18 coat protein temperature-sensitive-folding substitutions are in the I-domain, indicating its importance in folding and stability. Several are found on a positively charged face of the β-barrel that anchors the I-domain to a negatively charged surface of the coat protein HK97-core.Entities:
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Year: 2014 PMID： 24836025 PMCID： PMC4068711 DOI： 10.1016/j.str.2014.04.003
Source DB: PubMed Journal: Structure ISSN： 0969-2126 Impact factor: 5.006