Phylogeny and In Silico Structure Analysis of Major Capsid Protein (L1) Human Papillomavirus 45 from Indonesian Isolates

BACKGROUND: Human papillomavirus (HPV)-45 genotype circulates in high percentage in Bandung area - Indonesia, after HPV-16 and HPV-18. The aim of this study was to analyse variations of major capsid (L1) HPV-45 and its phylogeny. Furthermore in silico protein structure and epitope prediction was explored. METHODS: L1 gene of HPV-45 was amplified, sequenced and aligned. Phylogenetic tree had been built and compared with a complete L1 HPV-45 sequence. Structure and epitope prediction of L1 protein were then developed in silico. RESULTS: Of 5 L1 HPV-45 sequences collected, we have detected one variant of sub lineage A2 which was considered as a new variant, and two variants of B2. Superimposition of structure of these two variants with reference showed very similar structure. Furthermore, seven amino acid substitutions were found within these L1 variants of which two substitutions might change the polarity of corresponding amino acid I329T and S383G. The S383G occurred in surface loop (HI-Loop) of new L1 HPV-45 variant. CONCLUSION: Similar structure of Indonesian variants indicates that amino acids variations do not affect the L1 structure. However, one substitution with altered amino acid polarity found within the area of surface loop suggests a potential impact in antibody recognition and neutralization.