Crystal Structure of the Apicoplast DNA Polymerase from Plasmodium falciparum: The First Look at a Plastidic A-Family DNA Polymerase. Issue 20 (9th October 2016)

• Record Type: Journal Article
• Authors: Milton, Morgan E.; Choe, Jun-Yong; Honzatko, Richard B.; Nelson, Scott W.
• Is Part Of: Journal of molecular biology. Volume 428:Issue 20(2016:Oct. 15)
• Page Start: 3920
• Page End: 3934
• Publication Date: 2016-10-09
• Subjects: apPOL the polymerase domain encoded by the prex gene, polymerase derived from Prex, or apicoplast DNA polymerase -- Klenow the Klenow fragment of Escherichia coli DNA polymerase I -- BF the large fragment of the DNA polymerase from Geobacillus stearothermophilus -- T7 the DNA polymerase from bacteriophage T7 -- Taq the DNA polymerase from Thermus aquaticus -- polγ the DNA polymerase from human mitochondria -- N-apPOLexo − the D82N/E84Q mutant of apPOL with an N-terminal hexahistidine tag -- C-apPOLexo − the D82N/E84Q mutant of apPOL with an C-terminal hexahistidine tag -- NTR N-terminal region; Enzyme catalysis -- DNA exonuclease -- DNA–protein interactions -- bifunctional enzymes -- malaria; Molecular biology -- Periodicals; Biology -- Periodicals; Biochemistry -- Periodicals; Bacteriology -- Periodicals; Molecular Biology -- Periodicals; Biochemistry -- Periodicals; Biologie moléculaire -- Périodiques; Biologie -- Périodiques; Biochimie -- Périodiques; Moleculaire biologie; Biochemistry; Biology; Molecular biology; Periodicals; 572.805
• DOI: 10.1016/j.jmb.2016.07.016
• Languages: English
• ISSNs: 0022-2836

Abstract

Abstract: Plasmodium falciparum, the primary cause of malaria, contains a non-photosynthetic plastid called the apicoplast. The apicoplast exists in most members of the phylum Apicomplexa and has its own genome along with organelle-specific enzymes for its replication. The only DNA polymerase found in the apicoplast (apPOL) was putatively acquired through horizontal gene transfer from a bacteriophage and is classified as an atypical A-family polymerase. Here, we present its crystal structure at a resolution of 2.9 Å. P. falciparum apPOL, the first structural representative of a plastidic A-family polymerase, diverges from typical A-family members in two of three previously identified signature motifs and in a region not implicated by sequence. Moreover, apPOL has an additional N-terminal subdomain, the absence of which severely diminishes its 3ʹ to 5ʹ exonuclease activity. A compound known to be toxic to Plasmodium is a potent inhibitor of apPOL, suggesting that apPOL is a viable drug target. The structure provides new insights into the structural diversity of A-family polymerases and may facilitate structurally guided antimalarial drug design. Graphical Abstract: Highlights: Replication of the apicoplast genome of Plasmodium falciparum sustains malaria infections. Apicoplast DNA polymerase (apPOL) is a bacterially derived atypical A-family polymerase. Divergent structural features of apPOL revealed here are probed by mutagenesis. Truncation of the novel N-terminal region eliminates apPOL proofreading activity. A known antimalarial compound is an in vitro inhibitor of apPOL.