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Functional adaptation of the switch‐2 nucleotide sensor enables rapid processive translocation by myosin‐5
Author(s) -
Nagy Nikolett T.,
Sakamoto Takeshi,
Takács Balázs,
Gyimesi Máté,
Hazai Eszter,
Bikádi Zsolt,
Sellers James R.,
Kovács Mihály
Publication year - 2010
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fj.10-163998
Subject(s) - myosin , processivity , kinesin , atp hydrolysis , allosteric regulation , biophysics , nucleotide , biology , chromosomal translocation , chemistry , microbiology and biotechnology , atpase , biochemistry , microtubule , gene , enzyme , polymerase
Active site loops that are conserved across superfamilies of myosins, kinesins, and G proteins play key roles in allosteric coupling of NTP hydrolysis to interaction with track filaments or effector proteins. In this study, we investigated how the class‐specific natural variation in the switch‐2 active site loop contributes to the motor function of the intracellular transporter myosin‐5. We used single‐molecule, rapid kinetic and spectroscopic experiments and semiempirical quantum chemical simulations to show that the class‐specific switch‐2 structure including a tyrosine (Y439) in myosin‐5 enables rapid processive translocation along actin filaments by facilitating Mg 2+ ‐dependent ADP release. Using wild‐type control and Y439 point mutant myosin‐5 proteins, we demonstrate that the translocation speed precisely correlates with the kinetics of nucleotide exchange. Switch‐2 variants can thus be used to fine‐tune translocation speed while maintaining high processivity. The class‐specific variation of switch‐2 in various NTPase superfamilies indicates its general role in the kinetic tuning of Mg 2+ ‐dependent nucleotide exchange.—Nagy, N.T., Sakamoto, T., Takács, B., Gyimesi, M., Hazai, E., Bikádi, Z., Sellers, J.R., Kovács, M. Functional adaptation of the switch‐2 nucleotide sensor enables rapid processive translocation by myosin‐5. FASEB J . 24, 4480–4490 (2010). www.fasebj.org