>gnl|CDD|144991 pfam01612, 3_5_exonuc, 3'-5' exonuclease. This domain is responsible for the 3'-5' exonuclease proofreading activity of E. coli DNA polymerase I (polI) and other enzymes, it catalyses the hydrolysis of unpaired or mismatched nucleotides. This domain consists of the amino-terminal half of the Klenow fragment in E. coli polI it is also found in the Werner syndrome helicase (WRN), focus forming activity 1 protein (FFA-1) and ribonuclease D (RNase D). Werner syndrome is a human genetic disorder causing premature aging; 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. Length = 172

 Score = 43.8 bits (104), Expect = 2e-04
 Identities = 29/152 (19%), Positives = 50/152 (32%), Gaps = 25/152 (16%)

Query: 30  VILFAFGFDDHPVELWDCVHDPVMPQVLKEALENTDVTIVAHNSYFERTVLKACFNLDIP 89
             L      +    + D +      + LK  LE+ ++T V HN+ F+  VL   F   I 
Sbjct: 41  GCLIQISTGEGAYII-DPLALGDDLEGLKRLLEDPNITKVGHNAKFDLEVLARDF--GIK 97

Query: 90  IHRWICTLVLARSNGLPSALKAVGEALKLSSQKMEEGKELIARFCKGET---HECLYDRN 146
           +     T++ A   G P        +  L         +L  ++   E     +C   R 
Sbjct: 98  LENLFDTMLAAYLLGYP-------RSHSL--------DDLAEKYLGVELDKSEQCADWRA 142

Query: 147 KPNHREAWRLFGEYCKGDVTVTREIFKRLEPL 178
           +P   E       Y   D      ++ +L   
Sbjct: 143 RPLSEEQ----LRYAAEDADYLLRLYDKLRKE 170