5D0R

Crystal structure of human soluble Adenylyl Cyclase with the inhibitor bithionol

Summary for 5D0R

• Entry DOI: 10.2210/pdb5d0r/pdb
• Related: 4CLF 4CLK 4CLL 4CLP 4CLS 4CLT 4CLU 4CLW 4CLY 4CLZ 4CM2
• Descriptor: Adenylate cyclase type 10, 2,2'-sulfanediylbis(4,6-dichlorophenol), ACETATE ION, ... (7 entities in total)
• Functional Keywords: lyase
• Biological source: Homo sapiens (Human)
• Total number of polymer chains: 1
• Total formula weight: 55475.76

Authors

Kleinboelting, S.,Steegborn, C. (deposition date: 2015-08-03, release date: 2016-03-16, Last modification date: 2024-10-23)

Primary citation

Kleinboelting, S.,Ramos-Espiritu, L.,Buck, H.,Colis, L.,van den Heuvel, J.,Glickman, J.F.,Levin, L.R.,Buck, J.,Steegborn, C.
Bithionol Potently Inhibits Human Soluble Adenylyl Cyclase through Binding to the Allosteric Activator Site.
J.Biol.Chem., 291:9776-9784, 2016

PubMed Abstract: The signaling molecule cAMP regulates functions ranging from bacterial transcription to mammalian memory. In mammals, cAMP is synthesized by nine transmembrane adenylyl cyclases (ACs) and one soluble AC (sAC). Despite similarities in their catalytic domains, these ACs differ in regulation. Transmembrane ACs respond to G proteins, whereas sAC is uniquely activated by bicarbonate. Via bicarbonate regulation, sAC acts as a physiological sensor for pH/bicarbonate/CO2, and it has been implicated as a therapeutic target, e.g. for diabetes, glaucoma, and a male contraceptive. Here we identify the bisphenols bithionol and hexachlorophene as potent, sAC-specific inhibitors. Inhibition appears mostly non-competitive with the substrate ATP, indicating that they act via an allosteric site. To analyze the interaction details, we solved a crystal structure of an sAC·bithionol complex. The structure reveals that the compounds are selective for sAC because they bind to the sAC-specific, allosteric binding site for the physiological activator bicarbonate. Structural comparison of the bithionol complex with apo-sAC and other sAC·ligand complexes along with mutagenesis experiments reveals an allosteric mechanism of inhibition; the compound induces rearrangements of substrate binding residues and of Arg(176), a trigger between the active site and allosteric site. Our results thus provide 1) novel insights into the communication between allosteric regulatory and active sites, 2) a novel mechanism for sAC inhibition, and 3) pharmacological compounds targeting this allosteric site and utilizing this mode of inhibition. These studies provide support for the future development of sAC-modulating drugs.

PubMed: 26961873
DOI: 10.1074/jbc.M115.708255

Experimental method

X-RAY DIFFRACTION (2.24 Å)