Proteins Involved in Replication of the E. coli Chromosome
Process/Enzyme Gene Size (kDa) Molecules/Cell

Initiation

Dna-A dnaA 52 1,000
HU-a hupA 9.59 40,000
HU-b hupB 9.5 40,000
IHF-a himA 11.2 3,000
IHF-b himD 10.6 3,000
FIS fis 2 x 11.2 30,000
RNA polymerase 450 500
alpha (a ) rpoA 36.5
beta(b ) rpoB 151
beta prime (b ') rpoC 156
sigma (s ) rpoD 70
Initiation/Elongation
Helicase dnaB 6 x 50 20
DNAC dnaC 6 x 29 20
Primase dnaG 60 50-100
DNA Gyrase gryA 2 x 97 200
gryB 2 x 90
SSB ssb 4 x 19 500

Elongation

Polymerase III

918 10-20

(a e q b 2t 2)(a e q b 2g 2(d d 'c y )2)

a dnaE 130
t dnaX 71
g dnaX 47.5
b dnaN 40.6
d holA 34
d ' holB 32
e dnaO 27.5
c holC 14
y holD 12
q holE 10
Polymerase I polA 103 300
Ligase lig 75 300