Characterization of a novel muscle protein-Calsarcin

• Main Authors: Wei-Ping Huang, 黃瑋蘋
• Other Authors: Huichun Li
• Format: Others
• Language: zh-TW
• Published: 2004
• Online Access: http://ndltd.ncl.edu.tw/handle/99815775650334083640

碩士 === 慈濟大學 === 分子生物及細胞生物研究所 === 92 === Calsarcins, a novel family of striated muscle-specific proteins, reside in the Z-disc and interact with multiple Z-disc proteins like α-actinin as well as other proteins like calcineurin (a calcium/calmodulin-dependent serine /threonine phosphatase). Based on the studies of those calsarcin-binding proteins, it is hypothesized that calsarcin plays a role in maintenance of Z-disc structure and in the signal transduction in the striated muscle. Previous studies have identified three isoforms in the calsarcin family, calsarcin-1, calsarcin-2 and calsarcin-3. Protein sequence alignment of the three calsarcins revealed that the highest homology regions are at their amino and carboxyl termini, and the amino acid sequence is less conserved in their central part. Furthermore, none of the highly conserved calsarcin sequences show any significant homology to known proteins in the database, and no functional domains could be detected using a variety of bioinformatics predicting tools. The goal of this study is to characterize the structure of this novel protein with spectroscopic techniques including circular dichroism (CD) and fluorescence spectroscopy. The structural studies from CD reveal that the secondary structure of three calsarcin isoforms consist of about 9-22% α-helix, 30-35% β-conformation and 45-56% random coils, indicating that calsarcin has large disordered regions which lack a fixed tertiary structure. The results of Trp fluorescence show that both of the conserved Trp in calsarcin locate in a relatively buried position.