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 myoglo...

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Bibliographic Details
Published in:The Journal of Physical Chemistry Letters
Main Authors: Oang, KY Oang, Key Young, Kim, JG Kim, Jong Goo, Yang, C Yang, Cheolhee, Kim, TW Kim, Tae Wu, Kim, Y Kim, Youngmin, Kim, KH Kim, Kyung Hwan, Kim, J Kim, Jeongho, Ihee, H Ihee, Hyotcherl
Format: Article in Journal/Newspaper
Language:English
Published: AMER CHEMICAL SOC 2014
Subjects:
Sperm whale
Online Access:http://hdl.handle.net/10203/189227
https://doi.org/10.1021/jz4027425
Description
Summary: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.

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