Molecule of the Month: S-Nitrosylated Hemoglobin
Nitric oxide is attached to a conserved cysteine in hemoglobin and then released to control the flow of blood.
Signaling with NO
Exploring the Structure
The structure of S-nitrosylated hemoglobin (PDB entry 1buw) was determined by starting with crystals of hemoglobin with carbon monoxide, and then exposing them to nitric oxide gas. Since the carbon-monoxide-bound form has a similar structure as oxygenated hemoglobin, only small changes occurred when nitric oxide attached: two amino acids at the end of the chain (numbers 145 and 146) became disordered. To explore the structures of S-nitrosylated and carbonmonoxy hemoglobin (PDB entry 1hco), click on the image for an interactive JSmol.
Topics for Further Discussion
- Myoglobin in some cold-blooded animals is also regulated by nitric oxide. Take a look at PDB entry 2nrm to see S-nitrosylated myoglobin from tuna.
- The PDB archive includes many other S-nitrosylated proteins. Look at the list included on the ligand page for SNC (S-nitroso-cysteine).
Related PDB-101 Resources
- Browse Transport
- Browse You and Your Health
- Zhang, R., Hess, D.T., Qian, Z., Hausladen, A., Fonseca, F., Chaube, R., Reynolds, J.D., Stamler, J.S. (2015) Hemoglobin betaCys93 is essential for cardiovascular function and integrated response to hypoxia. Proc. Natl. Acad. Sci. USA 112, E2846.
- Evangelista, A.M., Kohr, M.J., Murphy, E. (2013) S-Nitrosylation: specificity, occupancy, and interaction with other post-translational modifications. Antioxid. Redox Signal. 19, 1209-1219.
- Gould, N., Paschalis-Thomas, D., Tenopoulou, M., Raju, K., Ischiropoulos, H. (2013) Regulation of protein function and signaling by reversible cysteine S-nitrosylation. J. Biol. Chem. 288, 26473-26479.
- Weichsel, A., Brailey, J.L., Montfort, W.R. (2007) Buried S-nitrosocysteine revealed in crystal structures of human thioredoxin. Biochemistry 46: 1219-1227.
- Chan, N.L., Rogers, P.H., Arnone, A. (1998) Crystal structure of the S-nitroso form of liganded human hemoglobin. Biochemistry 37: 16459-16464.
- Baldwin, J.M. (1980) The structure of human carbonmonoxy haemoglobin at 2.7 A resolution. J.Mol.Biol. 136: 103-128.
May 2019, David Goodsellhttp://doi.org/10.2210/rcsb_pdb/mom_2019_5