The impact of chromophore choice on the assembly kinetics and primary photochemistry of a red/green cyanobacteriochrome.
David BuhrkePublished in: Physical chemistry chemical physics : PCCP (2021)
Cyanobacteriochromes (CBCRs) are bi-stable photoreceptor proteins with high potential for biotechnological applications. Most of these proteins utilize phycocyanobilin (PCB) as a light-sensing co-factor, which is unique to cyanobacteria, but some variants also incorporate biliverdin (BV). The latter are of particular interest for biotechnology due to the natural abundance and red-shifted absorption of BV. Here, AmI-g2 was investigated, a CBCR capable of binding both PCB and BV. The assembly kinetics and primary photochemistry of AmI-g2 with both chromophores were studied in vitro. The assembly reaction with PCB is roughly 10× faster than BV, and the formation of a non-covalent intermediate was identified as the rate-limiting step in the case of BV. This step is fast for PCB, where the formation of the covalent thioether bond between AmI-g2 and PCB becomes rate-limiting. The photochemical quantum yields of the forward and backward reactions of AmI-g2 were estimated and discussed in the context of homologous CBCRs.
Keyphrases
- lps induced
- lipopolysaccharide induced
- acute myocardial infarction
- inflammatory response
- heart failure
- left ventricular
- copy number
- molecular dynamics
- oxidative stress
- dna methylation
- aqueous solution
- decision making
- gene expression
- mass spectrometry
- single molecule
- coronary artery disease
- high speed
- dna binding
- human health