The analysis of circumsporozoite-protein gene sequences from South Korean isolates of Plasmodium vivax

The amino-acid sequences corresponding to the circumsporozoite protein (CSP ) of Plasmodium vivax fall into two main types, VK210 and VK247, each of wh ich has a characteristic tandem repeat. When the repetitive domains of the CSP gene from six isolates of P. vivax from South Korea were sequenced they were found to show a total of 20 tandem amino-acid repeats, and repeat pat terns that are regular and distinct from those of other P. vivax isolates. The amino-acid sequences of the South Korean parasites were found to be mos t similar to those of three isolates from China (CH-3, CH-4, and CH-5) and, particularly, to one from North Korea. A sequence (AGGNAANKKAEDAGGNA) and two repeats of the sequence GGNA found in the North Korean parasites were f ound in all six isolates from South Korea. The South Korean parasites inves tigated appear phylogenetically identical and unique to the Korean peninsul a.