PDBsum entry 5ikx

Hydrolase

PDB id: 5ikx

Contents

Protein chains

569 a.a.

Waters ×376

PDB id:

5ikx

Name:

Hydrolase

Title:

Crystal structure of the alpha-esterase-7 carboxyl esterase (dimer), e3, from lucilia cuprina

Structure:

Carboxylic ester hydrolase. Chain: a, b. Engineered: yes

Source:

Lucilia cuprina. Green bottle fly. Organism_taxid: 7375. Gene: lcae7. Expressed in: escherichia coli. Expression_system_taxid: 562

Resolution:

2.19Å R-factor: 0.173 R-free: 0.209

Authors:

C.Jackson,N.Fraser

Key ref:

N.J.Fraser et al. (2016). Evolution of Protein Quaternary Structure in Response to Selective Pressure for Increased Thermostability. J Mol Biol, 428, 2359-2371. PubMed id: 27016206 DOI: 10.1016/j.jmb.2016.03.014

Date:

04-Mar-16 Release date: 22-Jun-16

Supersedes:

4fg5

Protein chains

Q25252  (Q25252_LUCCU) -  Carboxylic ester hydrolase from Lucilia cuprina

Seq: 570 a.a.

Struc: 569 a.a.*

* PDB and UniProt seqs differ at 7 residue positions (black crosses)

Enzyme reactions

• Enzyme class: E.C.3.1.1.- - ?????

DOI no: 10.1016/j.jmb.2016.03.014

J Mol Biol 428:2359-2371 (2016)

PubMed id: 27016206

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

N.J.Fraser, J.W.Liu, P.D.Mabbitt, G.J.Correy, C.W.Coppin, M.Lethier, M.A.Perugini, J.M.Murphy, J.G.Oakeshott, M.Weik, C.J.Jackson.

ABSTRACT

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 αE7 carboxylesterase from the Australian sheep blowfly, Lucilia cuprina, resulted in a thermostable variant, LcαE7-4a, 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 LcαE7-4a 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.