Evolution of Protein Quaternary Structure in Response to Selective Pressure for Increased Thermostability

JOURNAL OF MOLECULAR BIOLOGY

卷:428

Article

Fraser, Nicholas J.¹  Liu, Jian-Wei²  Mabbitt, Peter D.¹  Correy, Galen J.¹  Coppin, Chris W.²  Lethier, Mathilde³  Perugini, Matthew A.⁴  Murphy, James M.^5,6  Oakeshott, John G.²  Weik, Martin³  Jackson, Colin J.¹ 

[1] Australian Natl Univ, Res Sch Chem, GPO Box 4, Canberra, ACT 2601, Australia

[2] CSIRO, Land & Water Flagship, Canberra, ACT 0200, Australia

[3] Commissariat Energie Atom, Inst Biol Struct, F-38027 Grenoble, France

[4] La Trobe Univ, La Trobe Inst Mol Sci, Dept Biochem, Melbourne, Vic 3086, Australia

[5] Royal Melbourne Hosp, Walter & Eliza Hall Inst Med Res, Cell Signalling & Cell Death Div, 1G Royal Parade, Parkville, Vic 3052, Australia

[6] Univ Melbourne, Dept Med Biol, Melbourne, Vic 3050, Australia

关键词: oligomerization;    directed evolution;    thermostability;    carboxylesterase;    interface;   

DOI  :  10.1016/j.jmb.2016.03.014

来源: Elsevier

【 摘 要 】

Oligomerization has been suggested to be an important mechanism for increasing or maintaining the thermostability of proteins. Although it is evident that protein protein contacts can result in substantial stabilization in many extant proteins, evidence for evolutionary selection for oligomerization is largely indirect and little is understood of the early steps in the evolution of oligomers. A laboratory-directed evolution experiment that selected for increased thermostability in the alpha E7 carboxylesterase from the Australian sheep blowfly, Lucilia cuprina, resulted in a thermostable variant, Lc alpha E7-4a, that displayed increased levels of dimeric and tetrameric quaternary structure. A trade-off between activity and thermostability was made during the evolution of thermostability, with the higher-order oligomeric species displaying the greatest thermostability and lowest catalytic activity. Analysis of monomeric and dimeric Lc alpha E7-4a crystal structures revealed that only one of the oligomerization-inducing mutations was located at a potential protein protein interface. This work demonstrates that by imposing a selective pressure demanding greater thermostability, mutations can lead to increased oligomerization and stabilization, providing support for the hypothesis that oligomerization is a viable evolutionary strategy for protein stabilization. (C) 2016 Elsevier Ltd. All rights reserved.

【 授权许可】

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