A Caltech Library Service

Relaxation of structural constraints during Amicyanin unfolding

Kozak, John J. and Gray, Harry B. and Garza-López, Roberto A. (2018) Relaxation of structural constraints during Amicyanin unfolding. Journal of Inorganic Biochemistry, 179 . pp. 135-145. ISSN 0162-0134.

[img] PDF - Accepted Version
See Usage Policy.

[img] MS Excel (Table A) - Supplemental Material
See Usage Policy.

[img] PDF (Supplementary data) - Supplemental Material
See Usage Policy.


Use this Persistent URL to link to this item:


We study the thermal unfolding of amicyanin by quantifying the resiliency of the native state to structural perturbations. Three signatures characterizing stages of unfolding are identified. The first signature, lateral extension of the polypeptide chain, is calculated directly from the reported crystallographic data. Two other signatures, the radial displacement of each residue from Cu(II) and the angular spread in the chain as the protein unfolds, are calculated using crystallographic data in concert with a geometrical model we introduced previously (J.J. Kozak, H. B. Gray, R. A. Garza-López, J. Inorg. Biochem. 155(2016) 44–55). Particular attention is paid to the resiliency of the two beta sheets in amicyanin. The resiliency of residues in the near neighborhood of the Cu center to destabilization provides information on the persistence of the entatic state. Similarly, examining the resiliency of residues intercalated between structured regions (beta sheets, the alpha helix) provides a basis for identifying a “hydrophobic core.” A principal focus of our study is to compare results obtained using our geometrical model with the experimental results (C. La Rosa, D. Milardi, D. M. Grasso, M. P. Verbeet, G. W. Canters, L. Sportelli, R. Guzzi, Eur. Biophy. J.30(8),(2002) 559–570) on the denaturation of amicyanin, and we show that our results support a classical model proposed by these authors.

Item Type:Article
Related URLs:
URLURL TypeDescription
Additional Information:© 2017 Elsevier Inc. Received 5 July 2017, Revised 28 September 2017, Accepted 17 November 2017, Available online 22 November 2017. We thank NIH (R01 DK019038 to HBG) for support of work performed at the California Institute of Technology. Financial support for R.A.G.-L. was provided in part by grant # 52007555 to Pomona College from the Howard Hughes Medical Institute through the Precollege and Undergraduate Science Education Program. Molecular graphics images were produced using the Chimera package from the Computer Graphics Laboratory, University of California, San Francisco (supported by NIH P41RR-01081).
Funding AgencyGrant Number
NIHR01 DK019038
Howard Hughes Medical Institute (HHMI)52007555
Record Number:CaltechAUTHORS:20171122-090433323
Persistent URL:
Official Citation:John J. Kozak, Harry B. Gray, Roberto A. Garza-López, Relaxation of structural constraints during Amicyanin unfolding, In Journal of Inorganic Biochemistry, Volume 179, 2018, Pages 135-145, ISSN 0162-0134, (
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:83427
Deposited By: Tony Diaz
Deposited On:22 Nov 2017 17:14
Last Modified:13 Dec 2017 22:02

Repository Staff Only: item control page