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Cecropin XJ is a 41 amino acid cationic antimicrobial peptide originally isolated from the larvae of Bombyx mori.Previous studies have shown that Cecropin XJ is heat stable and display broad bacteriostatic activities.However,the information on molecular conformation of native Cecropin XJ remains unsolved.To better understand the structure-function relationship of this antimicrobial peptide,we deduced the secondary and tertiary structures of Cecropin XJ using the I-TASSER online server.The phylogenetic tree of Cecropin XJ constructed using an amino acid BLAST distance strategy predicts that Cecropin XJ belongs to Class I AMPs of the cecropin family.The predicted structure of Cecropin XJ was found to support the AMP pore-forming hypothesis,and the conserved motif 7K-9FKKI12 at the N-terminus may play an important role in the formation of the pore structure.The hydrophobic and electrostatic surface properties of Cecropin XJ indicated that it is an amphiphilic molecule.Moreover,the surface of Cecropin XJ was found to have a wide range of electrostatic potential.Four possible docking sites on the surface of Cecropin XJ were identified using COACH,a meta-server approach for protein-ligand binding site prediction.The present study is the first to identify potential docking sites for Mg2+ ions and adenosine diphosphate (ADP) in the Cecropin XJ molecule.