Identifikasi famili gen putatif penyandi protease inhibitor dengan pendekatan in silico komparatif pada genom Hevea brasiliensis Muell. Arg (Identification of putative gene family encoding protease inhibitors by in silico comparative analysis in Hevea brasiliensis Muell. Arg genome)
Authors: MARTIANSYAH Irfan , PUTRANTO Riza Arief , KHUMAIDA Nurul 
Published: November 2017

AbstractProtease inhibitors (PIs) are small proteins that form complexes with proteases and inhibits their proteolytic activity. Its potential application as an antimicrobial agent has been studied. Most of PIs' molecule size is around 8-22 kDa depending on their protein families.To date, on the basis of sequence homologies of inhibitor domains, PIs have been classified into 48 families in all organisms. In plant, more than 13 families of PIs have been identified but they were not widely identified in the rubber tree (Hevea brasiliensis Muell.Arg). In the present study, 40 putative HbPI genes, designated as HbPI01 to HbPI36, were identified from whole-genome sequence of rubber tree clone Reyan 7-33-97 using 7453 scaffolds available online in NCBI with the accession code: LVXX01000000. Multiple sequence alignment using MUSCLE algorithm discovered seven conserved motifs (Motifs I-VII) among HbPIs. Phylogenetic analysis of 50 and 36 PI amino acid residues of 32 scaffolds containing putative PI genes from Arabidopsis thaliana and H. brasiliensis showed three clusters (families): LTP-I, SERPIN and LTP-II. LTP-I has 23 putative HbPI genes (HbPI05 to HbPI27) and 12 AtPI genes. SERPIN, a family member of serine protease inhibitor group, has 11 putative HbPI genes (HbPI01 to HbPI04 and HbPI28 to HbPI34) and 22 AtPI genes. LTP-II has 2 putative HbPI genes (HbPI35 to HbPI36) and 16 AtPI genes. In conclusion, this work provides valuable information for further functional characterization of HbPI genes in H. brasiliensis.[Key words: protease inhibitor, genome-wide, scaffold, in silico, Hevea brasiliensis]. AbstrakProtease inhibitor (PI) merupakan protein yang membentuk kompleks dengan protease dan menghambat aktivitas proteolitik dari enzim tersebut. Potensi penggunaan protease inhibitor sebagai agensia antimikroba telah diketahui. Kebanyakan PI memiliki ukuran molekul sekitar 8-22 kDa bergantung pada familinya. Saat ini, PI dapat diklasifikasikan menjadi 48 famili di seluruh organisme berdasarkan kemiripan sekuen dari domain inhibitornya. Pada tanaman, lebih dari 13 famili PI telah diketahui tetapi pada tanaman karet (Hevea brasiliensis Muell.Arg) belum diidentifikasi. Pada penelitian ini, sebanyak 40 gen putatif penyandi PI (HbPI01 hingga HbPI36) telah berhasil diidentifikasi dari 7453 scaffold genom utuh tanaman karet klon Reyan 7-33-97 yang tersedia secara daring dengan kode aksesi LVXX01000000. Penjajaran sekuen menggunakan algoritma MUSCLE memper-lihatkan tujuh konservasi motif (Motif I-VIII) pada famili gen putatif HbPIs. Analisis pohon filogenetik dari tanaman Arabidopsis thaliana dan H. brasiliensis sebanyak 50 dan 36 sekuen residu asam amino dari 32 scaffold yang mengandung gen putatif PI menunjukkan adanya tiga klaster besar, yaitu famili LTP-I, SERPIN dan LTP-II. LTP-I terdiri dari 23 gen putatif HbPI (HbPI05 hingga HbPI27) dan 12 gen AtPI. SERPIN yang merupakan anggota kelas protease inhibitor serin terdiri dari 11 gen putatif HbPI (HbPI01hingga HbPI04 dan HbPI28 hingga HbPI34) dan 22 gen AtPI. LTP-II terdiri dari 2 gen putatif HbPI (HbPI35 hingga HbPI36) dan 16 gen AtPIs. Penelitian ini menghasilkan informasi penting untuk melakukan karakterisasi fungsional lebih mendalam pada gen HbPI tanaman karet ke depannya.[Kata kunci: protease inhibitor, genome-wide,scaffold, in silico, Hevea brasiliensis].