Exam 2: Major Proteins in DNA Replication Flashcards
helicase
moves along the fork unwinding dsDNA into two strands of ssDNA
SSBP
single-strand binding protein
keeps ssDNA strands apart
topoisomerases
type 1 and 2
eliminate excess supercoiling generated by unwinding
topoisomerase 1
nick, rotate, ligate
topoisomerase 2
double-strand break, pass through, rejoin
primase
makes short RNA primers on ssDNA strand
DNA polymerase 1
rips our RNA primer, puts in DNA, in steps of one nucleotide at a time
DNA polymerase 3
5’3’ polymerase
synthesizes DNA starting at an RNA primer
ligase
closes nicks in the sugar-phosphate backbone of one ssDNA strand in dsDNA
telomerase
enzyme that restores full-length telomeres in the chromosomes of gametes
renews telomeres in stem cells when they divide