Antibiotic resistant Escherichia coli strains are becoming more common recently. OmpA
is a very important antigen protein of E.
coli, which consists of two separate domains, N-terminal and C-terminal
domain. The N-terminal domain contains eight β- barrel regions that plays important roles in the multifaceted
functions of OmpA. In the present study, we cloned a mutant OmpA gene from a
multi-antibiotic resistant E. coli strain. Sequence analysis indicated that the N-terminal DNA sequence of the
mutant OmpA shared 81.05% homology with the modeled OmpA from E. coli K12 and the N-terminal amino
acid sequence of the mutant OmpA was 81.22% identical to that of the E. coli K12 OmpA. Moreover, several
amino acids located in the β-barrel
region were mutated. The mutant OmpA was expressed in BL21 suggested by
SDS-PAGE. Resistance to environmental stress assay indicated that the
N-terminus mutant OmpA still possessed excellent activities in pH, temperature
and osmotic pressure resistance. Our pre- sent study may supply insights into
better and deeper understand the relationships between OmpA N-terminal
regions and its functions in environmental stress conditions and the mechanisms
on antibiotic resistance of E. coli.