>cd06136 TREX1_2 Three prime repair exonuclease (TREX) 1 and 2 are closely related DEDDh-type DnaQ-like 3'-5' exonucleases. They contain three conserved sequence motifs known as ExoI, II, and III, with a specific Hx(4)D conserved pattern at ExoIII. These motifs contain four conserved acidic residues that participate in coordination of divalent metal ions required for catalysis. Both proteins play a role in the metabolism and clearance of DNA. TREX1 is the major 3'-5' exonuclease activity detected in mammalian cells. Mutations in the human TREX1 gene can cause Aicardi-Goutieres syndrome (AGS), which is characterized by perturbed innate immunity and presents itself as a severe neurological disease. TREX1 degrades ssDNA generated by aberrant replication intermediates to prevent checkpoint activation and autoimmune disease. There are distinct structural differences between TREX1 and 2 that point to different biological roles for these proteins. The main difference is the presence of about 7

Probab=98.55 E-value=1.1e-06 Score=58.18 Aligned_cols=79 Identities=24% Similarity=0.256 Sum_probs=51.4 Q ss_pred HHHHHHC--CCCCEEECCC-CHHHHHHHHHH---HCC-CCC--HHHHHHHHHHHHHHCCCHHHHHHHHHHHCCCCCCCCE Q ss_conf 7677732--3640230100-00168886542---000-000--0457898865211000000887776542002467520 Q gi|254780636|r 66 LVGMLVD--EKREKIFHYG-RFDIAVLFYTF---GVR-VRP--VFCTKIASRLTRTYTNQHGLKDNLKELLGINISKAQQ 136 (207) Q Consensus 66 L~~ll~d--~~i~KV~Hn~-~~D~~~L~~~~---gi~-~~~--i~DT~ias~l~~~~~~~~~L~~L~~~~lg~~ldK~~q 136 (207) T Consensus 88 ~~~F~~~~~~~~~LVAHNa~~FD~~fL~~e~~r~g~~~p~~~~~iDtL~l~r---~--~~~~L~~l~~~~~gi~~~~a-- 160 (177) T cd06136 88 IKLFLRRQPKPICLVAHNGNRFDFPILRSELERLGTKLPDDILCVDSLPAFR---E--LDQSLGSLYKRLFGQEPKNS-- 160 (177) T ss_pred HHHHHHHCCCCCEEEECCCHHCCHHHHHHHHHHCCCCCCCCCEEEEEHHHHH---H--HCCCHHHHHHHHCCCCCCCC-- T ss_conf 9999962677867996485123799999999986998998988998607645---5--06999999999759999877-- Q ss_pred ECCCCCCCCCHHHHHHHHHHHHHHHHHHH Q ss_conf 03656544323689999864599999999 Q gi|254780636|r 137 SSDWSADDLSDEQLQYAASDVVHLHALRL 165 (207) Q Consensus 137 ~SdW~~rpLs~~Qi~YAA~Dv~~l~~L~~ 165 (207) T Consensus 161 --------------HRAl~Da~at~~vfl 175 (177) T cd06136 161 --------------HTAEGDVLALLKCAL 175 (177) T ss_pred --------------CCCHHHHHHHHHHHC T ss_conf --------------784899999999975

HHsearch alignment for GI: 254780636 and conserved domain: cd06136