9nvl

Publication Abstract from PubMed

Extant F(1)-ATPases exhibit diverse rotational stepping behaviors-3-, 6-, or 9-step cycles-yet the evolutionary origin of these patterns remains unclear. Here, we used ancestral sequence reconstruction to infer the catalytic beta and non-catalytic alpha subunits of a putative ancestral F(1)-ATPase. We then fused their functionally critical domains into the thermostable F(1) from Bacillus PS3, yielding a stable chimeric enzyme. Cryo-EM revealed two distinct conformational states-binding and catalytic dwell states-separated by a ~34 degrees rotation of the gamma subunit, suggesting a fundamental six-step mechanism akin to that of extant six-stepping F(1)-ATPases. Single-molecule rotation assays with ATP and the slowly hydrolyzed ATP analog ATPgammaS demonstrated that the chimeric motor is intrinsically a six-stepper, pausing at binding and catalytic dwell positions separated by 32.1 degrees , although the binding dwell is significantly prolonged by an unknown mechanism. These findings indicate that F(1)-ATPase was originally a six-stepper and diversified into 3-, 6- and 9-step forms in evolutionary adaptation. Based on these results, we discuss plausible features of the entire F(o)F(1) complex, along with potential physiological contexts in the last universal common ancestor and related lineages.

Functional and structural characterization of F(1)-ATPase with common ancestral core domains in stator ring.,Suzuki AK, Furukawa R, Sobti M, Brown SHJ, Stewart AG, Akanuma S, Ueno H, Noji H Protein Sci. 2025 Nov;34(11):e70345. doi: 10.1002/pro.70345. PMID:41131942^[1]

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.