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Title: Mechanochemical coupling and bi-phasic force-velocity dependence in the ultra-fast ring ATPase SpoIIIE

Multi-subunit ring-shaped ATPases are molecular motors that harness chemical free energy to perform vital mechanical tasks such as polypeptide translocation, DNA unwinding, and chromosome segregation. Previously we reported the intersubunit coordination and stepping behavior of the hexameric ring-shaped ATPase SpoIIIE (Liu et al., 2015). Here we use optical tweezers to characterize the motor’s mechanochemistry. Analysis of the motor response to external force at various nucleotide concentrations identifies phosphate release as the likely force-generating step. Analysis of SpoIIIE pausing indicates that pauses are off-pathway events. Characterization of SpoIIIE slipping behavior reveals that individual motor subunits engage DNA upon ATP binding. Furthermore, we find that SpoIIIE’s velocity exhibits an intriguing bi-phasic dependence on force. We hypothesize that this behavior is an adaptation of ultra-fast motors tasked with translocating DNA from which they must also remove DNA-bound protein roadblocks. Based on these results, we formulate a comprehensive mechanochemical model for SpoIIIE.
Authors:
ORCiD logo [1] ;  [2] ;  [3] ; ORCiD logo [4]
  1. Univ. of California, Berkeley, CA (United States); Wyss Institute, Boston, MA (United States)
  2. Univ. of California, Berkeley, CA (United States); Harvard Medical School, Boston, MA (United States)
  3. Univ. of California, Berkeley, CA (United States)
  4. Univ. of California, Berkeley, CA (United States); Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)
Publication Date:
Grant/Contract Number:
AC02-05CH11231
Type:
Published Article
Journal Name:
eLife
Additional Journal Information:
Journal Volume: 7; Journal ID: ISSN 2050-084X
Publisher:
eLife Sciences Publications, Ltd.
Research Org:
Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States)
Sponsoring Org:
USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22)
Country of Publication:
United States
Language:
English
Subject:
59 BASIC BIOLOGICAL SCIENCES
OSTI Identifier:
1423709
Alternate Identifier(s):
OSTI ID: 1423711; OSTI ID: 1465444

Liu, Ninning, Chistol, Gheorghe, Cui, Yuanbo, and Bustamante, Carlos. Mechanochemical coupling and bi-phasic force-velocity dependence in the ultra-fast ring ATPase SpoIIIE. United States: N. p., Web. doi:10.7554/eLife.32354.
Liu, Ninning, Chistol, Gheorghe, Cui, Yuanbo, & Bustamante, Carlos. Mechanochemical coupling and bi-phasic force-velocity dependence in the ultra-fast ring ATPase SpoIIIE. United States. doi:10.7554/eLife.32354.
Liu, Ninning, Chistol, Gheorghe, Cui, Yuanbo, and Bustamante, Carlos. 2018. "Mechanochemical coupling and bi-phasic force-velocity dependence in the ultra-fast ring ATPase SpoIIIE". United States. doi:10.7554/eLife.32354.
@article{osti_1423709,
title = {Mechanochemical coupling and bi-phasic force-velocity dependence in the ultra-fast ring ATPase SpoIIIE},
author = {Liu, Ninning and Chistol, Gheorghe and Cui, Yuanbo and Bustamante, Carlos},
abstractNote = {Multi-subunit ring-shaped ATPases are molecular motors that harness chemical free energy to perform vital mechanical tasks such as polypeptide translocation, DNA unwinding, and chromosome segregation. Previously we reported the intersubunit coordination and stepping behavior of the hexameric ring-shaped ATPase SpoIIIE (Liu et al., 2015). Here we use optical tweezers to characterize the motor’s mechanochemistry. Analysis of the motor response to external force at various nucleotide concentrations identifies phosphate release as the likely force-generating step. Analysis of SpoIIIE pausing indicates that pauses are off-pathway events. Characterization of SpoIIIE slipping behavior reveals that individual motor subunits engage DNA upon ATP binding. Furthermore, we find that SpoIIIE’s velocity exhibits an intriguing bi-phasic dependence on force. We hypothesize that this behavior is an adaptation of ultra-fast motors tasked with translocating DNA from which they must also remove DNA-bound protein roadblocks. Based on these results, we formulate a comprehensive mechanochemical model for SpoIIIE.},
doi = {10.7554/eLife.32354},
journal = {eLife},
number = ,
volume = 7,
place = {United States},
year = {2018},
month = {3}
}