TY - JOUR
T1 - Multiple functional roles of the accessory I-domain of bacteriophage P22 coat protein revealed by NMR structure and CryoEM modeling
AU - Rizzo, Alessandro A.
AU - Suhanovsky, Margaret M.
AU - Baker, Matthew L.
AU - Fraser, Latasha C.R.
AU - Jones, Lisa M.
AU - Rempel, Don L.
AU - Gross, Michael L.
AU - Chiu, Wah
AU - Alexandrescu, Andrei T.
AU - Teschke, Carolyn M.
N1 - Funding Information:
This work was supported by grant R01 GM076661 to C.M.T. and a supplement to C.M.T. and A.T.A. M.L.B. is supported by grants R01 GM079429 and P41 GM103832 from the NIH. The NIH/National Institute of General Medical Sciences Mass Spectrometry Resource is supported by grant 8P41 GM103422-35. The Vermont Genetics Network is supported through the INBRE Program of the NIGMS (grant 8P20 GM103449), a component of the NIH. The contents are solely the responsibility of the authors and do not necessarily represent the official views of NIGMS or NIH. We thank Dr. Marie Cantino for use of the University of Connecticut Electron Microscopy Center and her expert guidance in electron microscopy and Mark Maciejewski (University of Connecticut Health Center) and Vitaliy Gorbatyuk (University of Connecticut) for assistance in NMR data collection.
PY - 2014/6/10
Y1 - 2014/6/10
N2 - Summary 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.
AB - Summary 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.
UR - http://www.scopus.com/inward/record.url?scp=84902328524&partnerID=8YFLogxK
U2 - 10.1016/j.str.2014.04.003
DO - 10.1016/j.str.2014.04.003
M3 - Article
C2 - 24836025
AN - SCOPUS:84902328524
SN - 0969-2126
VL - 22
SP - 830
EP - 841
JO - Structure
JF - Structure
IS - 6
ER -