TY - JOUR
T1 - CheY's acetylation sites responsible for generating clockwise flagellar rotation in Escherichia coli
AU - Fraiberg, Milana
AU - Afanzar, Oshri
AU - Cassidy, C. Keith
AU - Gabashvili, Alexandra
AU - Schulten, Klaus
AU - Levin, Yishai
AU - Eisenbach, Michael
N1 - Publisher Copyright:
© 2014 John Wiley & Sons Ltd.
PY - 2015/1/1
Y1 - 2015/1/1
N2 - Summary: Stimulation of Escherichia coli with acetate elevates the acetylation level of the chemotaxis response regulator CheY. This elevation, in an unknown mechanism, activates CheY to generate clockwise rotation. Here, using quantitative selective reaction monitoring mass spectrometry and high-resolution targeted mass spectrometry, we identified K91 and K109 as the major sites whose acetylation level in vivo increases in response to acetate. Employing single and multiple lysine replacements in CheY, we found that K91 and K109 are also the sites mainly responsible for acetate-dependent clockwise generation. Furthermore, we showed that clockwise rotation is repressed when residue K91 is nonmodified, as evidenced by an increased ability of CheY to generate clockwise rotation when K91 was acetylated or replaced by specific amino acids. Using molecular dynamics simulations, we show that K91 repression is manifested in the conformational dynamics of the β4α4 loop, shifted toward an active state upon mutation. Removal of β4α4 loop repression may represent a general activation mechanism in CheY, pertaining also to the canonical phosphorylation activation pathway as suggested by crystal structures of active and inactive CheY from Thermotoga maritima. By way of elimination, we further suggest that K109 acetylation is actively involved in generating clockwise rotation.
AB - Summary: Stimulation of Escherichia coli with acetate elevates the acetylation level of the chemotaxis response regulator CheY. This elevation, in an unknown mechanism, activates CheY to generate clockwise rotation. Here, using quantitative selective reaction monitoring mass spectrometry and high-resolution targeted mass spectrometry, we identified K91 and K109 as the major sites whose acetylation level in vivo increases in response to acetate. Employing single and multiple lysine replacements in CheY, we found that K91 and K109 are also the sites mainly responsible for acetate-dependent clockwise generation. Furthermore, we showed that clockwise rotation is repressed when residue K91 is nonmodified, as evidenced by an increased ability of CheY to generate clockwise rotation when K91 was acetylated or replaced by specific amino acids. Using molecular dynamics simulations, we show that K91 repression is manifested in the conformational dynamics of the β4α4 loop, shifted toward an active state upon mutation. Removal of β4α4 loop repression may represent a general activation mechanism in CheY, pertaining also to the canonical phosphorylation activation pathway as suggested by crystal structures of active and inactive CheY from Thermotoga maritima. By way of elimination, we further suggest that K109 acetylation is actively involved in generating clockwise rotation.
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U2 - 10.1111/mmi.12858
DO - 10.1111/mmi.12858
M3 - Article
C2 - 25388160
AN - SCOPUS:84920697308
VL - 95
SP - 231
EP - 244
JO - Molecular Microbiology
JF - Molecular Microbiology
SN - 0950-382X
IS - 2
ER -