RNA Therapeutics Institute Publications


A Hyperthermophilic Phage Decoration Protein Suggests Common Evolutionary Origin with Herpesvirus Triplex Proteins and an Anti-CRISPR Protein

UMMS Affiliation

Department of Biochemistry and Molecular Pharmacology; RNA Therapeutics Institute; Graduate School of Biomedical Sciences, Program in Biochemistry and Molecular Pharmacology

Publication Date


Document Type



Biochemistry, Biophysics, and Structural Biology | Genetics and Genomics


Virus capsids are protein shells that protect the viral genome from environmental assaults, while maintaining the high internal pressure of the tightly packaged genome. To elucidate how capsids maintain stability under harsh conditions, we investigated the capsid components of the hyperthermophilic phage P74-26. We determined the structure of capsid protein gp87 and show that it has the same fold as decoration proteins in many other phages, despite lacking significant sequence homology. We also find that gp87 is significantly more stable than mesophilic homologs. Our analysis of the gp87 structure reveals that the core "beta tulip" domain is conserved in trimeric capsid components across numerous double-stranded DNA viruses, including Herpesviruses. Moreover, this beta barrel domain is found in anti-CRISPR protein AcrIIC1, suggesting a mechanism for the evolution of this Cas9 inhibitor. Our work illustrates the principles for increased stability of gp87, and extends the evolutionary reach of the beta tulip domain.


anti-CRISPR protein, capsid decoration protein, double-stranded DNA virus, viral proteins

DOI of Published Version



Structure. 2018 Jul 3;26(7):936-947.e3. doi: 10.1016/j.str.2018.04.008. Epub 2018 May 17. Link to article on publisher's site

Journal/Book/Conference Title

Structure (London, England : 1993)

Related Resources

Link to Article in PubMed

PubMed ID