Vitreoscilla stercoraria hemoglobin and related proteins; single-domain globins
VtHb is homodimeric, and may both transport oxygen to terminal respiratory oxidases, and provide resistance to nitrosative stress. It has medium oxygen affinity and displays cooperative ligand-binding properties. VHb has biotechnological application, its expression in heterologous hosts (bacteria and plants) has improved growth and productivity under microaerobic conditions. Another member of this subfamily Campylobacter jejuni hemoglobin (Cgb) is monomeric, and plays a role in detoxifying NO. Along with a truncated globin Ctb, it is up-regulated by the transcription factor NssR in response to nitrosative stress.