YonK protein is expressed by the bacterial prophage SPbetaC [1]. It is a 63 residue protein that associates into a homo-octamer in the form of a beta-stranded barrel with four outer helical features at points of the compass. Its function is unknown.

1: Nucleotide sequence of the Bacillus subtilis temperate bacteriophage SPbetac2. Lazarevic V, Dusterhoft A, Soldo B, Hilbert H, Mauel C, Karamata D; Microbiology. 1999;145:1055-1067. PMID:10376821