Abstract:

Heat shock protein 70 (HSP70) is a highly conserved protein that plays a key role in protecting biological cells or tissues from heat or oxidative stress. Due to the continuous warming of the global environment and the widespread bleaching and death of corals, how corals respond to the stress resistance mechanism of continuous warming is a scientific research hotspot. However, current research on the characteristics of the HSP70 family in corals are relatively rare. In this study, 28 members of the HSP70 family were identified by analysis of the Sinularia acuta protein sequences under high temperature stress, all of which were acidic hydrophilic proteins with relatively stable structure. Subcellular localization showed that HSP70 was mainly found in coral nuclei and cytoplasm, with lesser amount in mitochondria and endoplasmic reticulum. Signal peptide predictions showed that 26 of the 28 HSP70 members did not have signal peptides, most of them do not secrete proteins and did not have a transmembrane structure. The phylogenetic tree showed that the members of the S. acuta HSP70 family can be clustered into 5 classes. Analysis of the structure and conserved regions of the hsp70 gene family of S. acuta predicted 10 motifs which could be divided into 5 subfamilies. The main secondary structure of the HSP70 protein in S. acuta was α-helix followed by random coiling. N-glycosylation sites were predicted in 25 of the 28 HSP70 family proteins, with the number of sites ranging from 1 to 9. All 28 HSP70 family proteins were predicted to have phosphorylation and O-glycosylation sites, with a total number in the range of 41~96 and 1~23, respectively. The results of this study on the HSP70 family lay the foundation for future research on the adaptive mechanisms of corals in response to global warming stress.

Key words: Sinularia acuta, heat shock proteins, HSP70 family, evolution