Verification of the Saccharina japonica Translocon Tic20 and its Localization in the Chloroplast Membrane in Diatoms

• Published in: International journal of molecular sciences 2019-08, Vol.20 (16), p.4000
• Main Authors: Chen, Zhihang, Wang, Xiuliang, Li, Shuang, Yao, Jianting, Shao, Zhanru, Duan, Delin
• Format: Article
• Language: English
• Subjects: Algae; Amino acids; Aquatic microorganisms; Binding sites; C-Terminus; Chloroplasts; Chloroplasts - chemistry; Cleavage; Cyanobacteria; Cytosol; Defects; Diatoms - chemistry; EF Hand Motifs; EF-hand; Endoplasmic reticulum; Fluorescence; Gene expression; Genes; Localization; Markers; Membrane Transport Proteins - analysis; Membranes; Microalgae - chemistry; Organisms; Peptides; Phaeodactylum tricornutum; Phaeophyceae - chemistry; Phylogenetics; Plankton; Plastids; Proteins; Saccharina japonica; Signal transduction; Stroma; subcellular localization; Tic20; transmembrane topology
• ISSN: 1422-0067; 1661-6596; 1422-0067
• DOI: 10.3390/ijms20164000

Tic20 is an important translocon protein that plays a role in protein transport in the chloroplast. The sequence of Tic20 was determined in the lower brown alga . Structural analysis of SjTic20 revealed a noncanonical structure consisting of an N-terminal non-cyanobacterium-originated EF-hand domain (a helix-loop-helix structural domain) and a C-terminal cyanobacterium-originated Tic20 domain. Subcellular localization and transmembrane analysis indicated that SjTic20 featured an "M"-type N -C -terminal orientation, with four transmembrane domains in the innermost membrane of the chloroplast in the microalga , and the EF-hand domain was entirely extruded into the chloroplast stroma. Our study provides information on the structure, localization, and topological features of SjTic20, and further functional analysis of SjTic20 in is needed.