Ring Separation Highlights the Protein-Folding Mechanism Used by the Phage EL-Encoded Chaperonin

Sudheer K. Molugu, Zacariah L. Hildenbrand, David Gene Morgan, Michael B. Sherman, Lilin He, Costa Georgopoulos, Natalia V. Sernova, Lidia P. Kurochkina, Vadim V. Mesyanzhinov, Konstantin A. Miroshnikov, Ricardo A. Bernal

Research output: Contribution to journalArticlepeer-review

13 Scopus citations

Abstract

Chaperonins are ubiquitous, ATP-dependent protein-folding molecular machines that are essential for all forms of life. Bacteriophage φEL encodes its own chaperonin to presumably fold exceedingly large viral proteins via profoundly different nucleotide-binding conformations. Our structural investigations indicate that ATP likely binds to both rings simultaneously and that a misfolded substrate acts as the trigger for ATP hydrolysis. More importantly, the φEL complex dissociates into two single rings resulting from an evolutionarily altered residue in the highly conserved ATP-binding pocket. Conformational changes also more than double the volume of the single-ring internal chamber such that larger viral proteins are accommodated. This is illustrated by the fact that φEL is capable of folding β-galactosidase, a 116-kDa protein. Collectively, the architecture and protein-folding mechanism of the φEL chaperonin are significantly different from those observed in group I and II chaperonins.

Original languageEnglish
Pages (from-to)537-546
Number of pages10
JournalStructure
Volume24
Issue number4
DOIs
StatePublished - Apr 5 2016

Funding

This work was supported by NIH- NIGMS SC3GM113805 , NSF - MRI 0923437 and Welch Foundation grant AH–1649 to Ricardo A. Bernal and Russian Fund for Basic Research grant # 11-04-00935 to Lidia P. Kurochkina. We would like to thank Dr. Judy Ellzey and Dr. Peter Cooke, Director of the New Mexico State University EM facility for his help with negative stain transmission electron microscopy. The Bio-SANS of the Center for Structural Molecular Biology (FWP ERKP291) at Oak Ridge National Laboratory is supported by the Office of Biological and Environmental Research of the US Department of Energy. Research at the High Flux Isotope Reactor of Oak Ridge National Laboratory was sponsored by the Scientific User Facilities Division, Office of Basic Energy Sciences , US Department of Energy.

FundersFunder number
Center for Structural Molecular BiologyFWP ERKP291
Scientific User Facilities Division
National Science FoundationMRI 0923437
National Institutes of Health
U.S. Department of Energy
National Institute of General Medical SciencesSC3GM113805
Welch FoundationAH–1649
Basic Energy Sciences
Biological and Environmental Research
Oak Ridge National Laboratory
Russian Foundation for Basic Research11-04-00935

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