Conformational Substates of Myoglobin Intermediate Resolved by Picosecond X-ray Solution Scattering.
Conformational substates of proteins are generally considered to play important roles in regulating protein functions, but an understanding of how they influence the structural dynamics and functions of the proteins has been elusive. Here, we investigate the structural dynamics of sperm whale myoglobin associated with the conformational substates using picosecond X-ray solution scattering. By applying kinetic analysis considering all of the plausible candidate models, we establish a kinetic model for the entire cycle of the protein transition in a wide time range from 100 ps to 10 ms. Four structurally distinct intermediates are formed during the cycle, and most importantly, the transition from the first intermediate to the second one (B→C) occurs biphasically. We attribute the biphasic kinetics to the involvement of two conformational substates of the first intermediate, which are generated by the interplay between the distal histidine and the photodissociated CO.
Center for Nanomaterials and Chemical Reactions, Institute for Basic Science (IBS) , Daejeon 305-701, Korea ; Department of Chemistry, Graduate School of Nanoscience & Technology (WCU), Korea Advanced Institute of Science and Technology (KAIST) , Daejeon 305-701, Korea.
Key Young
KY
Oang
Center for Nanomaterials and Chemical Reactions, Institute for Basic Science (IBS) , Daejeon 305-701, Korea ; Department of Chemistry, Graduate School of Nanoscience & Technology (WCU), Korea Advanced Institute of Science and Technology (KAIST) , Daejeon 305-701, Korea.
Jong Goo
JG
Kim
Center for Nanomaterials and Chemical Reactions, Institute for Basic Science (IBS) , Daejeon 305-701, Korea ; Department of Chemistry, Graduate School of Nanoscience & Technology (WCU), Korea Advanced Institute of Science and Technology (KAIST) , Daejeon 305-701, Korea.
Cheolhee
C
Yang
Center for Nanomaterials and Chemical Reactions, Institute for Basic Science (IBS) , Daejeon 305-701, Korea ; Department of Chemistry, Graduate School of Nanoscience & Technology (WCU), Korea Advanced Institute of Science and Technology (KAIST) , Daejeon 305-701, Korea.
Tae Wu
TW
Kim
Center for Nanomaterials and Chemical Reactions, Institute for Basic Science (IBS) , Daejeon 305-701, Korea ; Department of Chemistry, Graduate School of Nanoscience & Technology (WCU), Korea Advanced Institute of Science and Technology (KAIST) , Daejeon 305-701, Korea.
Youngmin
Y
Kim
Center for Nanomaterials and Chemical Reactions, Institute for Basic Science (IBS) , Daejeon 305-701, Korea ; Department of Chemistry, Graduate School of Nanoscience & Technology (WCU), Korea Advanced Institute of Science and Technology (KAIST) , Daejeon 305-701, Korea.
Kyung Hwan
KH
Kim
Department of Chemistry, Inha University , Incheon 402-751, Korea.
Jeongho
J
Kim
Center for Nanomaterials and Chemical Reactions, Institute for Basic Science (IBS) , Daejeon 305-701, Korea ; Department of Chemistry, Graduate School of Nanoscience & Technology (WCU), Korea Advanced Institute of Science and Technology (KAIST) , Daejeon 305-701, Korea.
Hyotcherl
H
Ihee