Multiple functional roles of the accessory I-domain of bacteriophage P22 coat protein revealed by NMR structure and CryoEM modeling.

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 intera

SUBMITTER: Rizzo AA 

PROVIDER: S-EPMC4068711 | biostudies-literature | 2014 Jun

REPOSITORIES: biostudies-literature