IN SILICO STUDY OF DEHALOGENASE TYPE DETERMINATION FROM BACILLUS CEREUS INDB1 AND ITS INTERACTION WITH VARIOUS CHLOROALKANOAT SUBSTRATES

• Main Author: Kinanti Ayu Putri, Ridha
• Format: Final Project
• Language: Indonesia
• Subjects: Kimia
• Online Access: https://digilib.itb.ac.id/gdl/view/57298
• Institution: Institut Teknologi Bandung

Organohalides, especially those containing chlorine, are toxic and persistent in the environment. Microorganism which produces haloacid dehalogenase can be used to break the covalent bond between carbon and halogen in halogenated aliphatic acid compounds. The use of microorganism to degrade organohalide waste is called bioremediation. Based on the mechanism, haloacid dehalogenase is divided into DehI and DehII. Previous research has succeeded in isolating the haloacid dehalogenase gene from Bacillus cereus IndB1, namely bcfd1 gene. This gene has also been successfully subcloned into pET-30(a) expression vector and expressed in Eschericia coli BL21 (DE3). In this study, we studied the amino acid sequence similarity of Bcfd1 with DehI and DehII, the presence of typical catalytic residues of DehI and DehII, the tersier structure of Bcfd1, and the structural similarity of Bcfd1 with DehI and DehII. The results indicate that Bcfd1 is DehII. The interaction of Bcfd1 with substrates 2-(mono, di, tri)-chloroacetic acid, 2-(D,L)- chloropropanoic acid, and 3-(mono,di, tri)-chloropropanoic acid was studied by molecular docking. The docking score of Bcfd1 for L-2-chloropropanoic acid is lower than that for D-2-chloropropanoic, indicating that Bcfd1 has a better affinity for L-2-chloropropanoic acid. Molecular binding to 2-(mono, di, tri)-chloroacetic acid and 3-(mono, di, tri)- chloropropanoic acid showed that the higher the number of chlorine atoms in the substrate, the more stable the Bcfd1-substrate complex. This is presumably because the chlorine group can form van der Waals interactions with residues Gly35, Arg36, Asn228, and Asn230 in the Bcfd1 catalytic pocket. Molecular docking of L-2-chloropropanoic acid and 3-chloropropanoic acid showed that Bcfd1 had a higher affinity for substrates with the chlorine group located at the alpha position.