The mechanism of pentabromopseudilin inhibition of myosin motor activity.
We have identified pentabromopseudilin (PBP) as a potent inhibitor of myosin-dependent processes such as isometric tension development and unloaded shortening velocity. PBP-induced reductions in the rate constants for ATP binding, ATP hydrolysis and ADP dissociation extend the time required per myosin ATPase cycle in the absence and presence of actin. Additionally, coupling between the actin and nucleotide binding sites is reduced in the presence of the inhibitor. The selectivity of PBP differs from that observed with other myosin inhibitors. To elucidate the binding mode of PBP, we crystallized the Dictyostelium myosin-2 motor domain in the presence of Mg(2+)-ADP-meta-vanadate and PBP. The electron density for PBP is unambiguous and shows PBP to bind at a previously unknown allosteric site near the tip of the 50-kDa domain, at a distance of 16 A from the nucleotide binding site and 7.5 A away from the blebbistatin binding pocket.
Fedorov
Roman
R
Research Centre for Structure Analysis, OE8830, Hannover Medical School, 30623 Hannover, Germany.
Böhl
Markus
M
Tsiavaliaris
Georgios
G
Hartmann
Falk K
FK
Taft
Manuel H
MH
Baruch
Petra
P
Brenner
Bernhard
B
Martin
René
R
Knölker
Hans-Joachim
HJ
Gutzeit
Herwig O
HO
Manstein
Dietmar J
DJ
D000255:Adenosine Triphosphate / Q000378:metabolism; D000818:Animals; D002645:Chickens; D007700:Kinetics; D008958:Models, Molecular; D009218:Myosins / Q000037:antagonists & inhibitors / Q000737:chemistry / Q000187:drug effects / Q000378:metabolism*; D011485:Protein Binding; D011487:Protein Conformation; D011758:Pyrroles / Q000494:pharmacology*; D051381:Rats; D012680:Sensitivity and Specificity
C101826:Myo5b protein, rat; D011758:Pyrroles; C094409:pentabromopseudilin; D000255:Adenosine Triphosphate; D009218:Myosins