Structure and function prediction analysis of Leptin

Abstract

Objective Leptin is an important protein hormone produced by white adipose tissue, which participates in the regulation of energy metabolism. Its research on improving metabolic mechanism after bariatric surgery is attracting more and more attention. The purpose of this study is to analyze Leptin’s structure and predict its function by bioinformatics, in order to further explore the role of leptin in the treatment of obesity by bariatric surgery. Methods Tools of ExPASy Server were employed to analyze the physicochemical properties of Leptin protein. The secondary structure was predicted by Jpred 4 and its three-level structure by Swiss-Mode. STRINGS database is used to predict interactions between Leptin and other proteins. Results The Leptin protein consisted of 167 amino acids with an isoelectric point of 5.88, an instability index of 47.52, and a fat coefficient of 110.84. There were 5 α-helicesand 1 β-sheet in the secondary structure prediction. The number of amino acids constituting alpha helix accounted for 50.9% of the total protein. Three possible tertiary structure models were simulated. From the prediction model, the protein was mainly alpha-helix, which was consistent with the prediction results of secondary structure. According to the trend of similar waveform, prediction model A is the most stable. The protein interaction network found that the protein families interacting with Leptin include Leptin receptor (LEPR), Signal transducer and activator of transcription 3 (STAT3), Peroxisome proliferator-activated receptor gamma (PPARG), Suppressor of cytokine signaling 3 (SOCS3), Glucagon (GCG), Tyrosine-protein kinase JAK2, Insulin receptor substrate 1 (IRS1), C-reactive protein (CRP), Tyrosine-protein phosphatase non-receptor type 1 (PTPN1) and Insulin (INS). Conclusion Leptin protein is an unstable lipophilic protein mainly composed of alpha-helix. It is secreted by white adipose tissue and mainly acts on the outside of cells. It inhibits the synthesis of adipocytes by participating in the regulation of sugar, fat and energy metabolism, thus reducing body weight. Key words: Leptin; Bariatric Surgery; Bioinformatics