Uncovering the Early Stages of Domain Melting in Calmodulin with Ultrafast Temperature-Jump Infrared Spectroscopy | Zendy

Lucy Minnes | Zendy; Gregory M. Greetham | Zendy; Daniel J. Shaw | Zendy; Ian P. Clark | Zendy; Robby Fritzsch | Zendy; Michael Towrie | Zendy; Anthony W. Parker | Zendy; Alistair J. Henry | Zendy; Richard J. Taylor | Zendy; Neil T. Hunt | Zendy

AI Assistant Blog Pricing

Home ZAIA Blog

Open Access

Uncovering the Early Stages of Domain Melting in Calmodulin with Ultrafast Temperature-Jump Infrared Spectroscopy

Author(s) -

Lucy Minnes,

Gregory M. Greetham,

Daniel J. Shaw,

Ian P. Clark,

Robby Fritzsch,

Michael Towrie,

Anthony W. Parker,

Alistair J. Henry,

Richard J. Taylor,

Neil T. Hunt

Publication year - 2019

Publication title -

the journal of physical chemistry b

Language(s) - English

Resource type - Journals

SCImago Journal Rank - 0.864

H-Index - 392

eISSN - 1520-6106

pISSN - 1520-5207

DOI - 10.1021/acs.jpcb.9b08870

Subject(s) - calmodulin , microsecond , temperature jump , crystallography , melting temperature , infrared , infrared spectroscopy , chemistry , molecular dynamics , biophysics , helix (gastropod) , relaxation (psychology) , spectroscopy , chemical physics , materials science , calcium , physics , computational chemistry , biology , ecology , organic chemistry , quantum mechanics , astronomy , neuroscience , snail , optics , composite material

The signaling protein calmodulin (CaM) undergoes a well-known change in secondary structure upon binding Ca 2+ , but the structural plasticity of the Ca 2+ -free apo state is linked to CaM functionality. Variable temperature studies of apo -CaM indicate two structural transitions at 46 and 58 °C that are assigned to melting of the C- and N-terminal domains, respectively, but the molecular mechanism of domain unfolding is unknown. We report temperature-jump time-resolved infrared (IR) spectroscopy experiments designed to target the first steps in the C-terminal domain melting transition of human apo -CaM. A comparison of the nonequilibrium relaxation of apo -CaM with the more thermodynamically stable holo -CaM, with 4 equiv of Ca 2+ bound, shows that domain melting of apo -CaM begins on microsecond time scales with α-helix destabilization. These observations enable the assignment of previously reported dynamics of CaM on hundreds of microsecond time scales to thermally activated melting, producing a complete mechanism for thermal unfolding of CaM.

The content you want is available to Zendy users.

Already have an account? Click here to sign in.

Having issues? You can contact us here

Accelerating Research