QSregVF_b is a family of short Pseudomonas proteins that are potential virulence factors. The structure of UniProtKB:Q9HY15 a secreted protein has been solved and deposited as PDB:3npd, from Pfam:PF13652. It is predicted that these two adjacent proteins form a single transcriptional unit based on the prediction that together they interact with their adjacent protein PotD, which is the putrescine-binding periplasmic protein in the polyamine uptake system comprising PotABCD. These two adjacent proteins are predicted to be quroum-sensing-regulated virulence factors [1].

1: Crystal structure of a putative quorum sensing-regulated protein (PA3611) from the Pseudomonas-specific DUF4146 family. Das D, Chiu HJ, Farr CL, Grant JC, Jaroszewski L, Knuth MW, Miller MD, Tien HJ, Elsliger MA, Deacon AM, Godzik A, Lesley SA, Wilson IA; Proteins. 2014;82:1086-1092. PMID:24174223