Aim:To examine the antimicrobial spectrum and functional structure of highmobility group nucleosomal binding domain 2(HMGN2).Methods:OMIGA pro-tein structure software was used to analyze the two-dimensional structure ofHMGN2.Synthetic short peptides were generated for studying the relationshipbetween function and structure.Prokaryotic expression vectors were constructedfor the holo-HMGN2 and its helical domain.Their E coil-based products werealso prepared for antimicrobial testing.The antimicrobial assay included minimaleffective concentration,minimal inhibitory concentration,and minimal bacteri-cidal concentration.Results:OMIGA protein structure software analysis revealeda transmembrane or-helical structure(the putative antimicrobial domain)locatedfrom position 18 to 48 of the HMGN2 protein sequence.The antimicrobial assayshowed that the MIC of the recombinant holo-HMGN2 against E coli ML-35p(anampicillin-resistance strain),Pseudomonas aeruginosa ATCC 27853 and Candidaalbicans ATCC 10231 were 12.5,25,and 100 rag/L,respectively.Against the samemicroorganisms,the MIC of the synthetic HMGN2 α-helical domain were 12.5,25,and 100 mg/L,respectively,that is,the same as with the recombinant form ofHMGN2.In contrast,recombinant holo-HMGN2 was inactive against Staphylo-coccus aureus ATCC 25923.The synthetic N-terminal and C-terminal fragments ofHMGN2 had no antimicrobial activity against E coli ML-35p,P aeruginosa ATCC27853 or C albicans ATCC 10231.Conclusion:HMGN2 showed potent antimi-crobial activity against E coli ML-35p,P aeruginosa ATCC 27853 and,to someextent,against C albicans ATCC 10231,but was inactive against S aureus ATCC25923 in these assay systems.Its α-helical structure may be essential for theantimicrobial activity of HMGN2. Aim: To examine the antimicrobial spectrum and functional structure of high motility group nucleosomal binding domain 2 (HMGN2). Methods: OMIGA pro-tein structure software was used to analyze the two-dimensional structure of HMGN2.Synthetic short peptides were generated for studying the relationship between function and structure. Prokaryotic expression vectors were constructed for the holo-HMGN2 and its helical domain. Their E coil-based products were prepared for antimicrobial testing. The antimicrobial assay included minimaleffective concentration, minimal inhibitory concentration, and minimal bacteri-cidal concentration. Results: OMIGA protein structure software analysis revealeda transmembrane or-helical structure (the putative antimicrobial domain) locatedfrom position 18 to 48 of the HMGN2 protein sequence. the antimicrobial assays showed that the MIC of the recombinant holo-HMGN2 against E. coli ML-35p (anampicillin-resistance strain ), Pseudomonas aeruginosa ATCC 27853 and Candida albicans ATCC 10 231 were 12.5, 25, and 100 rag / L, respectively. Of the same microorganisms, the MIC of the synthetic HMGN2 a-helical domains were 12.5, 25, and 100 mg / L, respectively, that, the same as with the recombinant form of HMGN2.In contrast, recombinant holo-HMGN2 was inactive against Staphylo-coccus aureus ATCC 25923. The synthetic N-terminal and C-terminal fragments of HMGN2 had no antimicrobial activity against E coli ML-35p, P aeruginosa ATCC 27853 or C albicans ATCC 10231 . Conlusion: HMGN2 showed potent antimi-crobial activity against E. coli ML-35p, P aeruginosa ATCC 27853 and, to someextent, against C albicans ATCC 10231, but was inactive against S. aureus ATCC25923 in these assay systems. Its α-helical structure may be essential for theantimicrobial activity of HMGN2.