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Published on: November 16, 2016
Cloning and characterization of the gene encoding for OMP-PD porin: the major Photobacterium damsela outer membrane
Anna Gribun1, Don J Katcoff, Gitit Hershkovits
1Health Sciences Research Center, Faculty of Life Sciences, Bar-Ilan University, Ramat Gan 52900, Israel.
Abstract:
The outer membrane protein of Photobacterium damsela (OMP-PD) and the gene encoding for this porin protein were isolated and characterized. The deduced amino acid sequence of the OMP-PD monomer has 338 amino acids and a calculated molecular weight of 36,951 Da. This sequence includes a 22-amino acid signal peptide at the N-terminal, which is not found when the monomer is located in the outer membrane. Native OMP-PD protein forms a trimeric structure of approximately 110 kDa. It exhibits resistance to proteases, and it can be cleaved only following denaturation by SDS. The degree of identity of the OMP-PD amino acid sequence to porins from the Enterobacteriaceae was only 24%. Identity to Vibrio or Photobacterium porins was 38% and 48%, respectively. Nevertheless, the multiple alignment of this sequence with other structurally defined Enterobacteria porins demonstrated that the location of the 16 beta-strands and eight external loops, including a larger external L3 loop, are conserved in OMP-PD. These results, together with the previously known ability of OMP-PD to form an ion channel in artificial liposomes, strongly support its role as a porin in P. damsela and will help further investigations into the role of OMP-PD in P. damsela pathogenicity.
Insights
Researchers isolated and characterized the outer membrane protein of Photobacterium damsela (OMP-PD). This porin protein
Area of Science:
- Microbiology
- Structural Biology
- Biochemistry
Background:
- Photobacterium damsela outer membrane protein (OMP-PD) is crucial for bacterial function.
- Understanding porin structure and function is vital in microbiology.
Purpose of the Study:
- To isolate and characterize the OMP-PD from Photobacterium damsela.
- To determine the structural and functional properties of OMP-PD.
- To investigate the role of OMP-PD in bacterial pathogenicity.
Main Methods:
- Protein isolation and characterization.
- Amino acid sequencing and molecular weight determination.
- Structural analysis through sequence alignment.
- Functional assays in artificial liposomes.
Main Results:
- OMP-PD monomer consists of 338 amino acids with a molecular weight of 36,951 Da.
- Native OMP-PD forms a stable trimeric structure resistant to proteases.
- Sequence analysis revealed conserved porin structural motifs, despite low identity to Enterobacteriaceae porins.
- OMP-PD forms ion channels in artificial liposomes.
Conclusions:
- OMP-PD functions as a porin in Photobacterium damsela.
- Structural conservation supports its role as a transmembrane channel.
- Further research can elucidate OMP-PD's contribution to P. damsela pathogenicity.
