Foreign PAS ligands regulate PAS domain function
Specific binding of a foreign core ligand to a PAS domain, wherein the PAS domain is predetermined, prefolded in its native state, and comprises a hydrophobic core that has no NMR-apparent a priori formed ligand cavity, is determined by (a) detecting a first NMR spectrum of the PAS domain in the presence of a foreign ligand; and (b) comparing the first NMR spectrum with a second NMR spectrum of the PAS domain in the absence of the ligand to infer the presence the ligand specifically bound within the hydrophobic core of the PAS domain. A functional surface binding specificity of a PAS domain, wherein the PAS domain is predetermined, prefolded in its native state, and comprises a hydrophobic core that has no NMR-apparent a priori formed ligand cavity, is changed by (a) introducing into the hydrophobic core of the PAS domain a foreign ligand of the PAS domain; and (b) detecting a change in the functional surface binding specificity of the PAS domain.
1 . A method of changing a functional surface binding specificity of a PAS domain, wherein the PAS domain is predetermined, prefolded in its native state, and comprises a hydrophobic core that has no NMR-apparent a priori formed ligand cavity, the method comprising the steps of:
introducing into the hydrophobic core of the PAS domain a foreign ligand of the PAS domain; and
detecting a resultant change in the functional surface binding specificity of the PAS domain.
2 . A method according to claim 1 , wherein the binding specificity is a change in intermolecular binding affinity of the PAS domain.
3 . A method according to claim 1 , wherein the binding specificity is a change in intramolecular binding affinity of the PAS domain.
4 . A method according to claim 1 , wherein the binding specificity is manifested as a change in kinase activity or specificity.
5 . A method according to claim 1 , wherein the binding specificity is manifested as a change in channel patency or specificity.
6 . A method according to claim 1 , wherein the PAS domain is expressed by and within a host cell or animal.
7 . A method according to claim 1 , wherein the PAS domain is expressed by and within a host cell or animal, and the ligand is foreign to the host.
8 . A method according to claim 1 , wherein the PAS domain is expressed by and within a host cell or animal, and the change is detected indirectly as a change in host cell or animal physiology precorrelated with the change in binding specificity.
9 . A method according to claim 4 , wherein the PAS domain is expressed by and within a host cell or animal, and the change is detected indirectly as a change in host cell or animal physiology precorrelated with the change in binding specificity.
10 . A method according to claim 5 , wherein the PAS domain is expressed by and within a host cell or animal, and the change is detected indirectly as a change in host cell or animal physiology precorrelated with the change in binding specificity.
11 . A method according to claim 1 , wherein the PAS domain is selected from the group consisting of PAS kinase PAS A, NPAS2 PAS A, HIF2a PAS B, HIF1a PASB, ARNT PAS B and human ether-a-go-go related gene (HERG) N-terminal PAS.
12 . A method according to claim 1 , wherein the PAS domain is part of a larger protein selected from the group consisting of PAS kinase, NPAS2, HIF2a, ARNT, HIF1 a and HERG protein.
13 . A method according to claim 8 , wherein the PAS domain is part of a larger protein selected from the group consisting of PAS kinase, NPAS2, HIF2a, ARNT, HIF1a and HERG protein.
14 . A method according to claim 9 , wherein the PAS domain is part of a larger protein selected from the group consisting of PAS kinase, NPAS2, HIF2a, ARNT, HIF1 a and HERG protein.
15 . A method according to claim 10 , wherein the PAS domain is part of a larger protein selected from the group consisting of PAS kinase, NPAS2, HIF2a, ARNT, HIF1 a and HERG protein.