Purification and characterization of a new DNA polymerase modulator from the hyperthermophilic archaeon Thermococcus fumicolans

During purification of the native alpha -like DNA polymerase from the hyper thermophilic euryarchaeote Thermococcus fumicolans, two activity peaks were detected after cation-exchange chromatography. One of the peaks (P-pol) wa s identified as: the T. fumicolans DNA polymerase and the second peak (P-f) was shown to contain a factor which increased the DNA polymerase activity over 70-fold when tested with activated calf thymus DNA as substrate. The f actor also stimulated nucleotide incorporation when using primed lambda DNA as substrate (approximate to 8-fold), while inducing a very large decrease in the turnover rate of the enzyme. The factor, therefore, maximizes the a bility of the DNA polymerase to synthesize small fragments, which is compat ible with DNA repair or lagging strand DNA replication. (C) 3000 Elsevier S cience Inc. All rights reserved.