Two amino acid substitutions convert a guanylyl cyclase, RetGC-1, into an adenylyl cyclase
- *Howard Hughes Medical Institute and Department of Biochemistry, Box 357370, University of Washington, Seattle, WA 98195; and †Laboratory of Molecular Biology, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD 20892-0580
-
Communicated by Lubert Stryer, Stanford University School of Medicine, Stanford, CA (received for review January 27, 1998)
Abstract
Guanylyl cyclases (GCs) and adenylyl cyclases (ACs) have fundamental roles in a wide range of cellular processes. Whereas GCs use GTP as a substrate to form cGMP, ACs catalyze the analogous conversion of ATP to cAMP. Previously, a model based on the structure of adenylate cyclase was used to predict the structure of the nucleotide-binding pocket of a membrane guanylyl cyclase, RetGC-1. Based on this model, we replaced specific amino acids in the guanine-binding pocket of GC with their counterparts from AC. A change of two amino acids, E925K together with C995D, is sufficient to completely alter the nucleotide specificity from GTP to ATP. These experiments strongly validate the AC-derived RetGC-1 structural model and functionally confirm the role of these residues in nucleotide discrimination.
Footnotes
-
↵ ‡ To whom reprint requests should be addressed. e-mail: jbhhh{at}u.washington.edu.
- ABBREVIATIONS:
- GC,
- guanylyl cyclase;
- AC,
- adenylyl cyclase;
- CAP,
- catabolite gene activator protein;
- GCAP,
- guanylyl cyclase activator protein
- Copyright © 1998, The National Academy of Sciences
