Multiple functional roles of the accessory I-domain of bacteriophage P22 coat protein revealed by NMR structure and CryoEM modeling.
Structure
; 22(6): 830-41, 2014 Jun 10.
Article
em En
| MEDLINE
| ID: mdl-24836025
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 ß-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 ß-barrel that anchors the I-domain to a negatively charged surface of the coat protein HK97-core.
Texto completo:
1
Base de dados:
MEDLINE
Assunto principal:
Bacteriófago P22
/
Proteínas do Capsídeo
Idioma:
En
Ano de publicação:
2014
Tipo de documento:
Article
País de afiliação:
Estados Unidos