What They Saw
They sequenced almost 6 kilobases somewhat downstream of the structural genes and found 6 open reading frames (ORFs), the last incomplete, so they sequenced some more to complete it. All 8 seemed to be a single operon. These genes are now called hoxV and hypABFCD (based on homology to E. coli genes).
They predicted that the middle 3 and last ORF (now called hypABF and hypD) would produce proteins good at binding Fe-S clusters. HypB has a histidine-rich region that might be good for binding nickel, and HypF has a zinc finger-like region. They have good homology to genes related to hydrogen metabolism in other organisms. They could be related to hydrogenase regulation or assembly, especially related to Ni and Fe; some (HypBF) have homology to other Ni-related proteins, such as urease.