3QRX

Chlamydomonas reinhardtii centrin bound to melittin

Summary for 3QRX

• Entry DOI: 10.2210/pdb3qrx/pdb
• Descriptor: Centrin, Melittin, CALCIUM ION, ... (4 entities in total)
• Functional Keywords: calcium-binding, ef-hand, cell division, calcium binding, metal binding protein-toxin complex, metal binding protein/toxin
• Biological source: Chlamydomonas reinhardtii; More
• Cellular location: Secreted: P01501
• Total number of polymer chains: 2
• Total formula weight: 22501.78

Authors

Schreiter, E.R. (deposition date: 2011-02-18, release date: 2011-10-26, Last modification date: 2023-09-13)

Primary citation

Sosa Ldel, V.,Alfaro, E.,Santiago, J.,Narvaez, D.,Rosado, M.C.,Rodriguez, A.,Gomez, A.M.,Schreiter, E.R.,Pastrana-Rios, B.
The structure, molecular dynamics, and energetics of centrin-melittin complex.
Proteins, 79:3132-3143, 2011

PubMed Abstract: Centrin is a calcium binding protein (CaBP) belonging to the EF-hand superfamily. As with other proteins within this family, centrin is a calcium sensor with multiple biological target proteins. We chose to study Chlamydomonas reinhardtii centrin (Crcen) and its interaction with melittin (MLT) as a model for CaBP complexes due to its amphipathic properties. Our goal was to determine the molecular interactions that lead to centrin-MLT complex formation, their relative stability, and the conformational changes associated with the interaction, when compared to the single components. For this, we determined the thermodynamic parameters that define Crcen-MLT complex formation. Two-dimensional infrared (2D IR) correlation spectroscopy were used to study the amide I', I'*, and side chain bands for (13)C-Crcen, MLT, and the (13)C-Crcen-MLT complex. This approach resulted in the determination of MLT's increased helicity, while centrin was stabilized within the complex. Herein we provide the first complete molecular description of centrin-MLT complex formation and the dissociation process. Also, discussed is the first structure of a CaBP-MLT complex by X-ray crystallography, which shows that MLT has a different binding orientation than previously characterized centrin-bound peptides. Finally, all of the experimental results presented herein are consistent with centrin maintaining an extended conformation while interacting with MLT. The molecular implications of these results are: (1) the recognition of hydrophobic contacts as requirements for initial binding, (2) minimum electrostatic interactions within the C-terminal end of the peptide, and (3) van der Waals interactions within MLTs N-terminal end are required for complex formation.

PubMed: 21989934
DOI: 10.1002/prot.23142

Experimental method

X-RAY DIFFRACTION (2.2 Å)