4IX6

Crystal structure of a Stt7 homolog from Micromonas algae soaked with ATP

Summary for 4IX6

• Entry DOI: 10.2210/pdb4ix6/pdb
• Related: 4IX3 4IX4 4IX5
• Descriptor: MsStt7d protein, ADENOSINE-5'-DIPHOSPHATE, MAGNESIUM ION, ... (4 entities in total)
• Functional Keywords: protein kinase, canonical protein kinase fold, atp binding, transferase
• Biological source: Micromonas (green algae)
• Total number of polymer chains: 2
• Total formula weight: 76368.82

Authors

Guo, J.,Wei, X.,Li, M.,Pan, X.,Chang, W.,Liu, Z. (deposition date: 2013-01-24, release date: 2013-10-02, Last modification date: 2024-03-20)

Primary citation

Guo, J.,Wei, X.,Li, M.,Pan, X.,Chang, W.,Liu, Z.
Structure of the catalytic domain of a state transition kinase homolog from Micromonas algae
Protein Cell, 4:607-619, 2013

PubMed Abstract: Under natural environments, plants and algae have evolved various photosynthetic acclimation mechanisms in response to the constantly changing light conditions. The state transition and long-term response processes in photosynthetic acclimation involve remodeling and composition alteration of thylakoid membrane. A chloroplast protein kinase named Stt7/STN7 has been found to have pivotal roles in both state transition and long-term response. Here we report the crystal structures of the kinase domain of a putative Stt7/STN7 homolog from Micromonas sp. RCC299 (MsStt7d) in the apo form and in complex with various nucleotide substrates. MsStt7d adopts a canonical protein kinase fold and contains all the essential residues at the active site. A novel hairpin motif, found to be a conserved feature of the Stt7/STN7 family and indispensable for the kinase stability, interacts with the activation loop and fixes it in an active conformation. We have also demonstrated that MsStt7d is a dualspecifi city kinase that phosphorylates both Thr and Tyr residues. Moreover, preliminary in vitro data suggest that it might be capable of phosphorylating a consensus N-terminal pentapeptide of light-harvesting proteins Micromonas Lhcp4 and Arabidopsis Lhcb1 directly. The potential peptide/protein substrate binding site is predicted based on the location of a pseudo-substrate contributed by the adjacent molecule within the crystallographic dimer. The structural and biochemical data presented here provide a framework for an improved understanding on the role of Stt7/STN7 in photosynthetic acclimation.

PubMed: 23794031
DOI: 10.1007/s13238-013-3034-9

Experimental method

X-RAY DIFFRACTION (1.6 Å)