Identification and characterization of outer membrane proteins G1a and G1b of Moraxella catarrhalis.
Moraxella catarrhalis is an important cause of otitis media, sinusitis, and lower respiratory tract infections in patients with chronic obstructive pulmonary disease. The purified outer membrane of M. catarrhalis contains a 29 kDa band, previously named outer membrane protein G1 (OMP G1). Polyclonal antiserum to the OMP G1 band was used to screen a genomic lambda phage library and the gene for OMP G1a was cloned and sequenced. Analysis of outer membrane by isoelectric focusing and amino-terminal protein sequence of the 29 kDa band revealed that the band is actually two individual proteins designated OMP G1a and OMP G1b. OMP G1a is a lipoprotein with an isoelectric point of 4. OMP G1b contains an unblocked amino-terminus and has an isoelectric point of 9. Analysis of the sequence of OMP G1a and OMP G1b from 25 clinical isolates revealed a high degree of conservation among strains. The sequence conservation of OMP G1a and OMP G1b among strains, combined with previous observations that OMP G1a and OMP G1b contain epitopes on the bacterial surface, indicate that OMP G1a and OMP G1b are potential vaccine antigens for M. catarrhalis.
Adlowitz
Diana G
DG
Department of Medicine, University at Buffalo, State University of New York, Buffalo, NY 14215, USA.
Hiltke
Thomas
T
Lesse
Alan J
AJ
Murphy
Timothy F
TF
D000595:Amino Acid Sequence; D001425:Bacterial Outer Membrane Proteins / Q000737:chemistry / Q000235:genetics*; D015698:Genomic Library; D008969:Molecular Sequence Data; D001936:Moraxella catarrhalis / Q000235:genetics*
D001425:Bacterial Outer Membrane Proteins; C494017:outer membrane protein G1a, Moraxella catarrhalis; C494018:outer membrane protein G1b, Moraxella catarrhalis