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The 3 × 120° rotary mechanism of Paracoccus denitrificans F1-ATPase is different from that of the bacterial and mitochondrial F1-ATPases.

Abstract：

:The rotation of Paracoccus denitrificans F1-ATPase (PdF1) was studied using single-molecule microscopy. At all concentrations of adenosine triphosphate (ATP) or a slowly hydrolyzable ATP analog (ATPγS), above or below Km, PdF1 showed three dwells per turn, each separated by 120°. Analysis of dwell time between steps showed that PdF1 executes binding, hydrolysis, and probably product release at the same dwell. The comparison of ATP binding and catalytic pauses in single PdF1 molecules suggested that PdF1 executes both elementary events at the same rotary position. This point was confirmed in an inhibition experiment with a nonhydrolyzable ATP analog (AMP-PNP). Rotation assays in the presence of adenosine diphosphate (ADP) or inorganic phosphate at physiological concentrations did not reveal any obvious substeps. Although the possibility of the existence of substeps remains, all of the datasets show that PdF1 is principally a three-stepping motor similar to bacterial vacuolar (V1)-ATPase from Thermus thermophilus This contrasts with all other known F1-ATPases that show six or nine dwells per turn, conducting ATP binding and hydrolysis at different dwells. Pauses by persistent Mg-ADP inhibition or the inhibitory ζ-subunit were also found at the same angular position of the rotation dwell, supporting the simplified chemomechanical scheme of PdF1 Comprehensive analysis of rotary catalysis of F1 from different species, including PdF1, suggests a clear trend in the correlation between the numbers of rotary steps of F1 and Fo domains of F-ATP synthase. F1 motors with more distinctive steps are coupled with proton-conducting Fo rings with fewer proteolipid subunits, giving insight into the design principle the F1Fo of ATP synthase.

journal_name

Proc Natl Acad Sci U S A

journal_title

Proceedings of the National Academy of Sciences of the United States of America

authors

Zarco-Zavala M,Watanabe R,McMillan DGG,Suzuki T,Ueno H,Mendoza-Hoffmann F,García-Trejo JJ,Noji H

doi

10.1073/pnas.2003163117

subject

Has Abstract

pub_date

2020-11-24 00:00:00

pages

29647-29657

issue

eissn

0027-8424

issn

1091-6490

pii

2003163117

journal_volume

117

pub_type

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The 3 × 120° rotary mechanism of Paracoccus denitrificans F1-ATPase is different from that of the bacterial and mitochondrial F1-ATPases.