5H4Y

Structural analysis of Ca(2+)-binding pocket of synaptotagmin 5 C2A domain

(2017) Int J Biol Macromol 95: 946-953

• PubMed: 27793683 Search on PubMed
• DOI: https://doi.org/10.1016/j.ijbiomac.2016.10.083
• Primary Citation of Related Structures:  
  5H4Y, 5H4Z


• PubMed Abstract: 
  

  Synaptotagmins constitute a family of multifunctional integral membrane proteins found predominantly on vesicles in neural and endocrine tissues. 17 isoforms of synaptotagmin family in mammals have been identified, 7 isoforms among them are known to be able to bind Ca ²⁺ via their C2 domains. This study presents the crystal structure of the first C2 domain (C2A domain) of synaptotagmin 5 complexed with Ca ²⁺ at 1.90Å resolution. Comparison of the Ca ²⁺ -binding pocket of synaptotagmin 5 C2A domain with other synaptotagmin C2 domains demonstrated that a serine residue locating at Ca ²⁺ -binding loop probably responsible to the conformational variation of Ca ²⁺ -binding pocket, and thus impacts the Ca ²⁺ -binding mechanism of C2 domain, which is verified by structural analysis of the serine mutant and Ca ²⁺ -binding assays via isothermal titration calorimetry. Alteration of Ca ²⁺ -binding mechanism might be correlated with different Ca ²⁺ response rates of synaptotagmins, which is the basis of the functions of synaptotagmins in regulating various types of Ca ²⁺ -triggered vesicle-membrane fusion processes.

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Organizational Affiliation: 

Key Laboratory of Applied Marine Biotechnology of Ministry of Education, Ningbo University, Ningbo, Zhejiang 315211, PR China; School of Marine Sciences, Ningbo University, Ningbo, Zhejiang 315211, PR China; Hefei National Laboratory for Physical Sciences at Microscale and School of Life Sciences, University of Science and Technology of China, Hefei, Anhui 230026, PR China; Key Laboratory of Structural Biology, Chinese Academy of Sciences, Hefei, Anhui 230026, PR China.