| Primary Identifier | IPR002562 | Type | Domain |
| Short Name | 3'-5'_exonuclease_dom |
| description | This entry represents the domain that is responsible for the 3'-5' exonuclease proofreading activity of Escherichia coli DNA polymerase I (polI) and other enzymes which catalyse the hydrolysis of unpaired or mismatched nucleotides. This domain consists of the amino-terminal half of the Klenow fragment in E. coli polI and is also found in the Bifunctional 3'-5' exonuclease/ATP-dependent helicase WRN (also known as Werner syndrome helicase), focus forming activity 1 protein (FFA-1) and ribonuclease D (RNase D) [].Werner syndrome is a human genetic disorder causing premature ageing; the WRN protein has helicase activity in the 3'-5' direction [, ]. The FFA-1 protein is required for formation of a replication foci and also has helicase activity; it is a homologue of the WRN protein []. RNase D is a 3'-5' exonuclease involved in tRNA processing. Also found in this family is the autoantigen PM/Scl thought to be involved in polymyositis-scleroderma overlap syndrome.This domain is also found in some DNA polymerases from phages, including the DNA polymerase from Escherichia phage T5, exonucleolytic activity [], and the DNA polymerase DpoZ from Acinetobacter phage SH-Ab 15497, which preferentially incorporates the non-canonical base aminoadenine/dZTP instead of adenine into the synthesized DNA []. |
