MPI für bioanorganische Chemie / MPI für bioanorganische Chemie |
|A LOV-domain-mediated blue-light-activated adenylate (adenylyl) cyclase from the cyanobacterium Microcoleus chthonoplastes PCC 7420|
|Authors:||Raffelberg, Sarah; Wang, Linzhu; Gao, Shiqiang; Losi, Aba; Gärtner, Wolfgang; Nagel, Georg|
|Date of Publication (YYYY-MM-DD):||2013|
|Title of Journal:||Biochemical Journal|
|Journal Abbrev.:||Biochem. J.|
|Abstract / Description:||Genome screening of the cyanobacterium Microcoleus chthonoplastes PCC 7420 identified a gene encoding a protein (483 amino acids, 54.2 kDa in size) characteristic of a BL (blue light)-regulated adenylate (adenylyl) cyclase function. The photoreceptive part showed signatures of a LOV (light, oxygen, voltage) domain. The gene product, mPAC (Microcoleus photoactivated adenylate cyclase), exhibited the LOV-specific three-peaked absorption band (lambda(max) = 450 nm) and underwent conversion into the photoadduct form (lambda(max) = 390 nm) upon BL-irradiation. The lifetime for thermal recovery into the parent state was determined as 16 s at 20 degrees C (25 s at 11 degrees C). The adenylate cyclase function showed a constitutive activity (in the dark) that was in-vitro-amplified by a factor of 30 under BL-irradiation. Turnover of the purified protein at saturating light and pH 8 is estimated to 1 cAMP/mPAC per s at 25 degrees C (2 cAMP/mPAC per s at 35 degrees C). The lifetime of light-activated cAMP production after a BL flash was similar to 14 s at 20 degrees C. The temperature optimum was determined to 35 degrees C and the pH optimum to 8.0. The value for half-maximal activating light intensity is 6 Wm(2) (at 35 degrees C). A comparison of mPAC and the BLUF (BL using FAD) protein bPAC (Beggiatoa PAC), as purified proteins and expressed in Xenopus laevis oocytes, yielded higher constitutive activity for mPAC in the dark, but also when illuminated with BL.|
|Free Keywords:||adenylate (adenylyl) cyclase; cAMP; cyclic nucleotide-gated channel; flavin photoreceptor; LOV (light, oxygen, voltage) domain; photoactivation|
|External Publication Status:||published|
|Communicated by:||N. N.|
|Affiliations:||MPI für bioanorganische Chemie|
|External Affiliations:||Wang, L.; Gao, S.; Nagel, G.; Univ Würzburg, D-97082 Wurzburg, Germany.
Losi, A.; Univ Parma, Dept Phys & Earth Sci, I-43124 Parma, Italy.
|Identifiers:||ISI:000326664100010 [ID No:1] |
ISSN:0264-6021 [ID No:2]
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