Borrelia burgdorferi BB0462 ORF encodes unknown function protein with 110 amino acids.Blast search in protein databases and its secondary structure prediction by JUFO program showed conserved hypothetical BB0462 protein was very similar to the members of YbaB family in either amino acid composition or protein structure.Co-transformation of BB0462 ORF and oppA upstream regulation DNA into E.coli host cells and β-galacotosidase assay demonstrated BB0462 protein enhanced the transcription activity of oppAⅤ promoter

but didn’t affect those of other oppAⅠ-Ⅳ promoters.Gel mobility shift assay also confirmed BB0462 protein only bound to oppAⅤ upstream regulation DNA fragment.Both β-galacotosidase assay and gel mobility shift assay demonstrated that BB0462 protein might play a role in the transcriptional activation of oppAⅤ promoter.