Denmark – Spectrometers – Procurement of spectrofluorometer

Mutations in the archetypal Ca2+-sensor calmodulin (CaM) are associated with life-threat-ening cardiac arrhythmias in children. Yet, population wide sequencing studies now reveal carriers of CaM mutations who are seemingly healthy. This extreme segregation of phenotypes warrants a deeper understanding of the molecular impact of CaM mutations, to understand why some variants result in a pathogenic phenotype and other variants do not. Thus, the aim of this project is to determine which human Calmodulin mutations impair the ability to bind Ca2+-ions and decode intracellular Ca2+-signals to target proteins. We wish to upgrade our experimental platform with a new spectrofluorometer for measuring the Ca2+-affinity of CaM variants. Calcium binding to the CaM N- and C-lobe can be followed by intrinsic Phe and Tyr fluorescence, respectively. The change in fluorescence signal upon Ca2+-binding is small and demands high sensitivity and spectral specificity to be accurately and reliably measured. The optical configuration of the spectrofluorometer we seek needs to meet these requirements. The instrument should further be equipped with a fluorescence anisotropy module to enable characterization of CaM binding to TAMRA-labeled CaM-binding domains from target proteins.