gamma DNA polymerase complex / positive regulation of DNA-directed DNA polymerase activity / mitochondrial chromosome / Strand-asynchronous mitochondrial DNA replication / mitochondrial DNA replication / DNA replication proofreading / single-stranded DNA 3'-5' DNA exonuclease activity / 加水分解酵素; エステル加水分解酵素; 5'-リン酸モノエステル産生エンドデオキシリボヌクレアーゼ / DNA metabolic process / DNA polymerase processivity factor activity ...gamma DNA polymerase complex / positive regulation of DNA-directed DNA polymerase activity / mitochondrial chromosome / Strand-asynchronous mitochondrial DNA replication / mitochondrial DNA replication / DNA replication proofreading / single-stranded DNA 3'-5' DNA exonuclease activity / 加水分解酵素; エステル加水分解酵素; 5'-リン酸モノエステル産生エンドデオキシリボヌクレアーゼ / DNA metabolic process / DNA polymerase processivity factor activity / 付加脱離酵素(リアーゼ); 炭素-酸素リアーゼ類; その他の炭素-酸素リアーゼ / mitochondrial nucleoid / 5'-deoxyribose-5-phosphate lyase activity / base-excision repair, gap-filling / DNA polymerase binding / 3'-5' exonuclease activity / mitochondrion organization / Transcriptional activation of mitochondrial biogenesis / base-excision repair / DNA-templated DNA replication / protease binding / double-stranded DNA binding / DNA-directed DNA polymerase / in utero embryonic development / DNA-directed DNA polymerase activity / mitochondrial matrix / chromatin binding / protein-containing complex / mitochondrion / DNA binding / identical protein binding / cytoplasm 類似検索 - 分子機能
DNA-directed DNA-polymerase, family A, mitochondria / DNA mitochondrial polymerase, exonuclease domain / POLG2, C-terminal / : / DNA mitochondrial polymerase exonuclease domain / Glycyl-tRNA synthetase/DNA polymerase subunit gamma-2 / Anticodon-binding / Anticodon binding domain / Anticodon-binding domain superfamily / DNA-directed DNA polymerase, family A, conserved site ...DNA-directed DNA-polymerase, family A, mitochondria / DNA mitochondrial polymerase, exonuclease domain / POLG2, C-terminal / : / DNA mitochondrial polymerase exonuclease domain / Glycyl-tRNA synthetase/DNA polymerase subunit gamma-2 / Anticodon-binding / Anticodon binding domain / Anticodon-binding domain superfamily / DNA-directed DNA polymerase, family A, conserved site / DNA polymerase family A signature. / DNA-directed DNA polymerase, family A, palm domain / DNA polymerase A domain / Class II Aminoacyl-tRNA synthetase/Biotinyl protein ligase (BPL) and lipoyl protein ligase (LPL) / Ribonuclease H-like superfamily / DNA/RNA polymerase superfamily 類似検索 - ドメイン・相同性
DNA polymerase subunit gamma-1 / DNA polymerase subunit gamma-2 類似検索 - 構成要素
National Institutes of Health/National Institute Of Allergy and Infectious Diseases (NIH/NIAID)
米国
National Institutes of Health/National Institute of General Medical Sciences (NIH/NIGMS)
米国
引用
ジャーナル: bioRxiv / 年: 2026 タイトル: Pol γ possesses separate metal binding sites for polymerase and strand displacement functions. 要旨: Accurate replication of mitochondrial genome (mtDNA) integrity, which is essential for cellular metabolism and energy supply, relies primarily on DNA polymerase gamma (Pol γ), Twinkle helicase, and ...Accurate replication of mitochondrial genome (mtDNA) integrity, which is essential for cellular metabolism and energy supply, relies primarily on DNA polymerase gamma (Pol γ), Twinkle helicase, and mitochondrial single-stranded DNA binding protein (mtSSB). Twinkle alone exhibits little helicase activity while reports indicate that Pol γ displays from modest to limited unwinding activity. This led us to dissect Pol γ strand displacement activity using structural, biochemical and in silico approaches. Here, we show that human Pol γ carries out robust strand displacement synthesis at physiological concentrations of divalent metal ions which reveals that distinct metal-binding sites can independently regulate DNA synthesis and unwinding activities. We further showed that Pol γ can displace RNA/DNA hybrid with comparable efficiency as DNA/DNA duplex, representing a key implication on RNA primer removal to preserve mtDNA integrity. Our cryo-electron microscopy structures of Pol γ complexed with a template containing downstream dsDNA and an incoming nucleotide revealed the structural mechanism for the strand displacement activity. We identified four conformational states that represent successive stages of DNA unwinding, accompanied by coordinated rearrangement of the downstream DNA and Pol γ elements that mediate strand displacement. This work establishes biochemical and structural mechanisms of Pol γ strand displacement activity, providing fundamental insight into human mitochondrial DNA replication and integrity.