Diversity in Rhodococcus Sequences on NCBI

Downloading all the alpha chain amino acid sequences of nitrile hydratases of Rhodococcus origin from NCBI, you get over 100 sequences. By eliminating all the ones which are from PDB entries, you get 98 sequences. By using the usual amino acid sequence tag to identify which metal centre present, you get 68 iron-centred NHases and 24 cobalt-centred NHases, and six bits of rubbish. Of the iron centred ones, 61 have the VCSLC tag starting at position 109. None of the remaining have the metal binding region starting in the same place, and range from 96 to 149. There is much more of a spread with the cobalt centred sequences if you track the equivalent tag, as the histogram below shows.