Crystal structure of the "cab"-type beta class carbonic anhydrase from the archaeon Methanobacterium thermoautotrophicum.
Strop, P., Smith, K.S., Iverson, T.M., Ferry, J.G., Rees, D.C.(2001) J Biol Chem 276: 10299-10305
- PubMed: 11096105 
- DOI: https://doi.org/10.1074/jbc.M009182200
- Primary Citation of Related Structures:  
1G5C - PubMed Abstract: 
The structure of the "cab"-type beta class carbonic anhydrase from the archaeon Methanobacterium thermoautotrophicum (Cab) has been determined to 2.1-A resolution using the multiwavelength anomalous diffraction phasing technique. Cab exists as a dimer with a subunit fold similar to that observed in "plant"-type beta class carbonic anhydrases. The active site zinc is coordinated by protein ligands Cys(32), His(87), and Cys(90), with the tetrahedral coordination completed by a water molecule. The major difference between plant- and cab-type beta class carbonic anhydrases is in the organization of the hydrophobic pocket. The structure reveals a Hepes buffer molecule bound 8 A away from the active site zinc, which suggests a possible proton transfer pathway from the active site to the solvent.
Organizational Affiliation: 
Biochemistry Option, California Institute of Technology, Pasadena, California 91125, USA.