Intra-species variations in gene and protein composition of Bdellovibrio bacteriovorous HD100, the predatory microorganism that preys on other Gramnegative bacteria, have been analyzed. Major sources of variations at the gene level are gene expression, local GC-bias and horizontal gene transfer and those at the protein level are alcoholicity, hydropathicity, aromaticity and frequencies of charged residues. Some cell-wall surface anchor family proteins and transporter proteins with distinct composition, secondary structures and potential disordered structures contribute significantly to intra-proteome compositional variation. The study, in contradiction to earlier reports, identifies some genes with atypical codon usage, presumably acquired by Bdellovibrio in recent past. The majority of the closest homologs of these putative HGTs belong to different classes of Gram-negative bacteria and it is hypothesized that these genes might have been incorporated into Bdellovibrio genome as a result of its interaction with prey cells.