Plasmodium vivax merozoite surface protein 3 (PvMSP3) is encoded by a multi-gene family. Of these, PvMSP3α, PvMSP3β and PvMSP3γ, are considered to be vaccine targets. Despite comprehensive analyses of PvMSP3α and PvMSP3β, little is known about structural and sequence diversity in PvMSP3γ. Analysis of 118 complete pvmsp3γ sequences from diverse endemic areas of Thailand and 9 reported sequences has shown 86 distinct haplotypes. Based on variation in insert domains, pvmsp3γ can be classified into 3 types, i.e. Belem, Salvador I and NR520. Imperfect nucleotide repeats were found in six regions of the gene; none encoded tandem amino acid repeats. Predicted coiled-coil heptad repeats were abundant in the protein and displayed variation in length and location. Interspersed phase shifts occurred in the heptad arrays that may have an impact on protein structure. Polymorphism in pvmsp3γ seems to be generated by intragenic recombination and driven by natural selection. Most P. vivax isolates in Thailand exhibit population structure, suggesting limited gene flow across endemic areas. Phylogenetic analysis has suggested that insert domains could have been subsequently acquired during the evolution of pvmsp3γ. Sequence and structural diversity of PvMSP3γ may complicate vaccine design due to alteration in predicted immunogenic epitopes among variants.

间日疟原虫裂殖子表面蛋白3（PvMSP3）由一个多基因家族编码。其中，PvMSP3α，PvMSP3β和PvMSP3γ被视为疫苗靶标。尽管对PvMSP3α和PvMSP3β进行了全面分析，但对PvMSP3γ的结构和序列多样性知之甚少。对来自泰国不同流行地区的118个完整pvmsp3γ序列进行分析，并报告了9个序列，结果显示86种不同的单倍型。基于插入域的变化，pvmsp3γ可以分为3种类型，即Belem，Salvador I和NR520。在该基因的六个区域发现了不完善的核苷酸重复序列。没有编码的串联氨基酸重复。预测的卷曲螺旋七肽重复序列在蛋白质中含量丰富，并显示出长度和位置的变化。七肽阵列中出现散布的相移，可能会对蛋白质结构产生影响。pvmsp3γ中的多态性似乎是由基因内重组产生的，并由自然选择驱动。泰国的大多数间日疟原虫分离株均表现出种群结构，这表明跨流行地区的基因流有限。系统发育分析表明，在pvmsp3γ的进化过程中可能会随后获得插入域。由于变体之间预测的免疫原性表位的改变，PvMSP3γ的序列和结构多样性可能会使疫苗设计复杂化。