Cloning of a novel gene yrbB, encoding a protein located in the spore integument of Bacillus subtilis

A DNA fragment (2.7 kbp) containing three deduced open reading frames, orf1, orf2 and orf3 (partial sequence), was isolated from the genomic library of Bacillus subtilis using an antiserum raised against spore integument, and was sequenced. orf2 was 519 nucleotides long and encoded a protein of 172 amino acids with a predicted molecular size of 19,552, corresponding to the protein which reacted with the antiserum. Immunoelectron microscopic observation indicated that YrbB, the product of orf2, was located within the spore integument, mainly in the cortex layer with a part in the inner region of the coat layer.