Serotype-Specific Biochemical and Immunological Signatures of Dengue Virus Envelope Proteins

Dengue is an arboviral disease of global significance caused by Orthoflavivirus denguei (DENV), which has four antigenically distinct serotypes. The envelope (E) protein plays a critical role in viral entry and eliciting immune responses. This study aimed to compare the biochemical and immunological properties of the E protein across the four DENV serotypes using in silico approaches. E protein reference sequences were retrieved from RefSeq and analyzed with various bioinformatics tools. Sequence alignment revealed identities ranging from 63.08% to 77.69%. Biochemical analysis showed minimal variation in molecular weight and isoelectric point; however, the net charge of DENV-3 E protein was notably lower. Secondary structure predictions indicated a predominance of alpha-helices in DENVs-1/2, while DENVs-3/4 featured more beta-sheets. Post-translational modification analysis revealed mostly casein kinase II phosphorylation sites across all serotypes, with DENV-4 uniquely presenting also tyrosine kinase sites. Amino acids W231/D341 in DENV-1, Q86 in DENVs-2/4, and D87/D339 in DENV-3 showed maximum antigenicity scores in B cell recognition, while the human leukocyte antigen (HLA) alleles B*08:01/B*39:01 and DRB4*01:01, recognized by T cells, presented the highest number of predicted epitopes for the different DENV serotypes. Conservation analysis showed that the major antigenic regions highlighted in this study are highly conserved among contemporary DENV isolates despite the genetic variability observed within each serotype. These findings suggest that subtle structural differences in the E protein may contribute to distinct immunogenic profiles, highlighting candidate regions for future investigation.