6HCS

Crystal structure of CaM-peptide complex containing AzF at position 108

Summary for 6HCS

• Entry DOI: 10.2210/pdb6hcs/pdb
• Descriptor: Calmodulin-1, Calcium/calmodulin-dependent protein kinase type II subunit beta, CALCIUM ION, ... (4 entities in total)
• Functional Keywords: calmodulin, unnatural amino acid, azf, protein binding
• Biological source: Homo sapiens (Human); More
• Total number of polymer chains: 8
• Total formula weight: 88246.88

Authors

Creon, A.,Josts, I.,Tidow, H. (deposition date: 2018-08-16, release date: 2018-12-05, Last modification date: 2024-10-23)

Primary citation

Creon, A.,Josts, I.,Niebling, S.,Huse, N.,Tidow, H.
Conformation-specific detection of calmodulin binding using the unnatural amino acid p-azido-phenylalanine (AzF) as an IR-sensor.
Struct Dyn, 5:064701-064701, 2018

PubMed Abstract: Calmodulin (CaM) is a very conserved, ubiquitous, eukaryotic protein that binds four Ca ions with high affinity. It acts as a calcium sensor by translating Ca signals into cellular processes such as metabolism, inflammation, immune response, memory, and muscle contraction. Calcium binding to CaM leads to conformational changes that enable Ca/CaM to recognize and bind various target proteins with high affinity. The binding mode and binding partners of CaM are very diverse, and a consensus binding sequence is lacking. Here, we describe an elegant system that allows conformation-specific detection of CaM-binding to its binding partners. We incorporate the unnatural amino acid p-azido-phenylalanine (AzF) in different positions of CaM and follow its unique spectral signature by infrared (IR)-spectroscopy of the azido stretching vibration. Our results suggest that the AzF vibrational probe is sensitive to the chemical environment in different CaM/CaM-binding domain (CaMBD) complexes, which allows differentiating between different binding motifs according to the spectral characteristics of the azido stretching mode. We corroborate our results with a crystal structure of AzF-labelled CaM (CaM108AzF) in complex with a binding peptide from calmodulin-dependent protein kinase IIα identifying the structural basis for the observed IR frequency shifts.

PubMed: 30474048
DOI: 10.1063/1.5053466

Experimental method

X-RAY DIFFRACTION (2 Å)