Cloning and expression of the first gene for biodegrading microcystin LR by Sphingopyxis sp. USTB-05.
J Environ Sci (China)
; 24(10): 1816-22, 2012.
Article
in En
| MEDLINE
| ID: mdl-23520852
ABSTRACT
Harmful cyanobacterial blooms are a growing environmental problem worldwide in natural waters, the biodegradation is found to be the most efficient method for removing microcystins (MCs) produced by harmful cyanobacteria. Based on the isolation of a promising bacterial strain of Sphingopyxis sp. USTB-05 for biodegrading MCs, we for the first time cloned and expressed a gene USTB-05-A (HM245411) that is responsible for the first step in the biodegradation of microcystin LR (MC-LR) in E. coli DH5alpha, with a cloning vector of pGEM-T easy and an expression vector of pGEX-4T-1, respectively. The cell-free extracts (CE) of recombinant E. coli DH5alpha containing USTB-05-A had high activity for biodegrading MC-LR. The initial MC-LR concentration of 40 mg/L was completely biodegraded within 1 hr in the presence of CE with a protein concentration of 0.35 mg/mL. Based on an analysis of the liquid chromatogram-mass spectrum (LC-MS), the enzyme encoded by gene USTB-OS-A was found to be active in cleaving the target peptide bond between 3-amino-9-methoxy-2,6, 8-trimethyl-10-phenyl-deca-4,6-dienoic acid (Adda) and arginine of MC-LR, and converting cyclic MC-LR to linear MC-LR as a first product that is much less toxic than parent MC-LR, which offered direct evidence for the first step on the pathway of MC-LR biodegradation by Sphingopyxis sp. USTB-05.
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Collection:
01-internacional
Database:
MEDLINE
Main subject:
Bacterial Proteins
/
Gene Expression Regulation, Bacterial
/
Alphaproteobacteria
/
Microcystins
Language:
En
Journal:
J Environ Sci (China)
Journal subject:
SAUDE AMBIENTAL
Year:
2012
Document type:
Article
Affiliation country:
China