The Need for Speed: Run-On Oligomer Filament Formation Provides Maximum Speed with Maximum Sequestration of Activity
AuthorBarahona, Claudia J
Basantes, L Emilia
Tompkins, Kassidy J
Heitman, Desirae M
Chukwu, Barbara I
Sanchez, Jonathan L
Park, Chad K
Horton, N C
AffiliationUniv Arizona, Dept Mol & Cellular Biol
filament forming enzymes
MetadataShow full item record
PublisherAMER SOC MICROBIOLOGY
CitationBarahona, C. J., Basantes, L. E., Tompkins, K. J., Heitman, D. M., Chukwu, B. I., Sanchez, J., ... & Horton, N. C. (2019). The Need for Speed: Run-On Oligomer Filament Formation Provides Maximum Speed with Maximum Sequestration of Activity. Journal of virology, 93(5), e01647-18.
JournalJOURNAL OF VIROLOGY
RightsCopyright © 2019 American Society for Microbiology. All Rights Reserved.
Collection InformationThis item from the UA Faculty Publications collection is made available by the University of Arizona with support from the University of Arizona Libraries. If you have questions, please contact us at email@example.com.
AbstractHere, we investigate an unusual antiviral mechanism developed in the bacterium Streptomyces griseus. SgrAI is a type II restriction endonuclease that forms run-on oligomer filaments when activated and possesses both accelerated DNA cleavage activity and expanded DNA sequence specificity. Mutations disrupting the run-on oligomer filament eliminate the robust antiphage activity of wild-type SgrAI, and the observation that even relatively modest disruptions completely abolish this anti-viral activity shows that the greater speed imparted by the run-on oligomer filament mechanism is critical to its biological function. Simulations of DNA cleavage by SgrAI uncover the origins of the kinetic advantage of this newly described mechanism of enzyme regulation over more conventional mechanisms, as well as the origin of the sequestering effect responsible for the protection of the host genome against damaging DNA cleavage activity of activated SgrAI. IMPORTANCE This work is motivated by an interest in understanding the characteristics and advantages of a relatively newly discovered enzyme mechanism involving filament formation. SgrAI is an enzyme responsible for protecting against viral infections in its host bacterium and was one of the first such enzymes shown to utilize such a mechanism. In this work, filament formation by SgrAI is disrupted, and the effects on the speed of the purified enzyme as well as its function in cells are measured. It was found that even small disruptions, which weaken but do not destroy filament formation, eliminate the ability of SgrAI to protect cells from viral infection, its normal biological function. Simulations of enzyme activity were also performed and show how filament formation can greatly speed up an enzyme's activation compared to that of other known mechanisms, as well as to better localize its action to molecules of interest, such as invading phage DNA.
Note6 month embargo; published online: 19 February 2019
VersionFinal accepted manuscript
SponsorsNational Science Foundation [MCB-1410355]; Office of the Director, National Institutes of Health [S10OD013237]; National Institute of General Medical Sciences of the National Institutes of Health [T32GM008659]