Polymeric forms of H-NOX proteins

A method of treating a disease or condition in a mammal in need thereof comprising administering to the mammal a trimeric H-NOX protein comprising three H-NOX monomers, wherein each H-NOX monomer comprises a T. tengcongensis H-NOX domain and a trimerization domain, wherein the H-NOX domain in each H-NOX monomer comprises a L144F substitution, and wherein the trimerization domain in each H-NOX monomer is a foldon domain of bacteriophage T4 fibritin,

• wherein the disease or condition is a cardiovascular disease in which blood volume is lost or O2 carrying capacity is reduced, loss of blood, a trauma in which blood volume is lost or O2 carrying capacity is reduced, hemorrhage, hemorrhagic shock, a surgery, hemodilution, a wound, a diabetic ulcer, anemia, a tissue ischemia, a stroke, a transient ischemic attack, myocardial stunning and hibernation, acute angina, unstable angina, emerging angina, myocardial infarction, cardioplegia, or traumatic brain injury.