5X4U

PAC from Oscillatoriaacuminata after 60 seconds photoactivation

Summary for 5X4U

• Entry DOI: 10.2210/pdb5x4u/pdb
• Related: 5X4T 5X4V
• Descriptor: Photoactivated adenylyl cyclase, FLAVIN MONONUCLEOTIDE (3 entities in total)
• Functional Keywords: camp, bluf domain, optogenetics, photoactivation, allostery, lyase
• Biological source: Cyanobacteria
• Total number of polymer chains: 1
• Total formula weight: 41475.17

Authors

Ohki, M.,Park, S.-Y. (deposition date: 2017-02-14, release date: 2017-07-26, Last modification date: 2024-03-27)

Primary citation

Ohki, M.,Sato-Tomita, A.,Matsunaga, S.,Iseki, M.,Tame, J.R.H.,Shibayama, N.,Park, S.Y.
Molecular mechanism of photoactivation of a light-regulated adenylate cyclase.
Proc. Natl. Acad. Sci. U.S.A., 114:8562-8567, 2017

PubMed Abstract: The photoactivated adenylate cyclase (PAC) from the photosynthetic cyanobacterium (OaPAC) detects light through a flavin chromophore within the N-terminal BLUF domain. BLUF domains have been found in a number of different light-activated proteins, but with different relative orientations. The two BLUF domains of OaPAC are found in close contact with each other, forming a coiled coil at their interface. Crystallization does not impede the activity switching of the enzyme, but flash cooling the crystals to cryogenic temperatures prevents the signature spectral changes that occur on photoactivation/deactivation. High-resolution crystallographic analysis of OaPAC in the fully activated state has been achieved by cryocooling the crystals immediately after light exposure. Comparison of the isomorphous light- and dark-state structures shows that the active site undergoes minimal changes, yet enzyme activity may increase up to 50-fold, depending on conditions. The OaPAC models will assist the development of simple, direct means to raise the cyclic AMP levels of living cells by light, and other tools for optogenetics.

PubMed: 28739908
DOI: 10.1073/pnas.1704391114

Experimental method

X-RAY DIFFRACTION (1.8 Å)