PDBsum entry 5c8v

Hydrolase

PDB id: 5c8v

Contents

Protein chain

566 a.a.

Waters ×208

PDB id:

5c8v

Name:

Hydrolase

Title:

Lucilia cuprina alpha esterase 7: gly137asp

Structure:

Carboxylic ester hydrolase. Chain: a. Engineered: yes. Mutation: yes

Source:

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

Resolution:

2.01Å R-factor: 0.188 R-free: 0.245

Authors:

G.J.Correy,P.D.Mabbitt,C.J.Jackson

Key ref:

P.D.Mabbitt et al. (2016). Conformational Disorganization within the Active Site of a Recently Evolved Organophosphate Hydrolase Limits Its Catalytic Efficiency. Biochemistry, 55, 1408-1417. PubMed id: 26881849 DOI: 10.1021/acs.biochem.5b01322

Date:

26-Jun-15 Release date: 09-Mar-16

Protein chain

Q25252  (Q25252_LUCCU) -  Carboxylic ester hydrolase from Lucilia cuprina

Seq: 570 a.a.

Struc: 566 a.a.*

* PDB and UniProt seqs differ at 8 residue positions (black crosses)

Enzyme reactions

• Enzyme class: E.C.3.1.1.- - ?????

DOI no: 10.1021/acs.biochem.5b01322

Biochemistry 55:1408-1417 (2016)

PubMed id: 26881849

Conformational Disorganization within the Active Site of a Recently Evolved Organophosphate Hydrolase Limits Its Catalytic Efficiency.

P.D.Mabbitt, G.J.Correy, T.Meirelles, N.J.Fraser, M.L.Coote, C.J.Jackson.

ABSTRACT

The evolution of new enzymatic activity is rarely observed outside of the laboratory. In the agricultural pest Lucilia cuprina, a naturally occurring mutation (Gly137Asp) in α-esterase 7 (LcαE7) results in acquisition of organophosphate hydrolase activity and confers resistance to organophosphate insecticides. Here, we present an X-ray crystal structure of LcαE7:Gly137Asp that, along with kinetic data, suggests that Asp137 acts as a general base in the new catalytic mechanism. Unexpectedly, the conformation of Asp137 observed in the crystal structure obstructs the active site and is not catalytically productive. Molecular dynamics simulations reveal that alternative, catalytically competent conformers of Asp137 are sampled on the nanosecond time scale, although these states are less populated. Thus, although the mutation introduces the new reactive group responsible for organophosphate detoxification, the catalytic efficiency appears to be limited by conformational disorganization: the frequent sampling of low-energy nonproductive states. This result is consistent with a model of molecular evolution in which initial function-changing mutations can result in enzymes that display only a fraction of their catalytic potential due to conformational disorganization.