>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=98.50 E-value=2.1e-07 Score=72.58 Aligned_cols=142 Identities=15% Similarity=0.195 Sum_probs=80.7 Q ss_pred CCCCCCCCCCCCCCC-CCCCCCEEECCCCCCCCCCC---------CC---CEE---CCCCC------CCCCCCC-CCCCC Q ss_conf 523233222433110-01244201025776654434---------55---023---13744------3334565-00178 Q gi|254780277|r 389 SASFKIITDTMDAFH-SKPIAIAISTLDQKDDTSFK---------VE---TIF---IDLSV------HTSQDST-GKNTL 445 (976) Q Consensus 389 ~ia~DtETt~ld~~~-~~ivGisls~~~~~~~~~~~---------~~---~~y---ip~~~------~~~~d~~-~~~~~ 445 (976) T Consensus 1 fvv~D~ETTGL~~~~~~rIiEI~av~v~~~~~~~~~~~~~~~~~i~d~~~~lvnP~~~Ip~~it~itGIt~emv~~~~~~ 80 (177) T cd06136 1 FVFLDLETTGLPKHNRPEITELCLVAVHRDHLLNTSRDKPALPRVLDKLSLCFNPGRAISPGASEITGLSNDLLEHKAPF 80 (177) T ss_pred CEEEEEECCCCCCCCCCCEEEEEEEEEECCCCCCCCCCCCCCCCEEEEEEEEECCCCCCCHHHHHHCCCCHHHHHCCCCH T ss_conf 98998678997988998558999999977874443111245662142256764879938876887518899998159981 Q ss_pred HHHHHHHHHHHHCC--CCCHHHHCCC-CHHHHHHH----HCCCCCC-C--CCCHHHHHHHHCCCCCCCCHHHHHHHHCCC Q ss_conf 89999744442022--2100110032-12378898----6188666-4--210023455431687667724667762244 Q gi|254780277|r 446 TKEILSYLKKFFEN--EHFLKIGHNI-KYDKLVLH----RYGISMR-G--FEDIMLMSYVLDSGRSSHDIASIAQKWLSY 515 (976) Q Consensus 446 ~~evl~~L~~lle~--~~i~kIgHN~-KfD~~~L~----~~GI~l~-~--i~DTmlaayLLdp~~~~~~L~~la~~yL~~ 515 (976) T Consensus 81 ~~~~~~~~~~F~~~~~~~~~LVAHNa~~FD~~fL~~e~~r~g~~~p~~~~~iDtL~l~r~~-----~~~L~~l~~~~~gi 155 (177) T cd06136 81 DSDTANLIKLFLRRQPKPICLVAHNGNRFDFPILRSELERLGTKLPDDILCVDSLPAFREL-----DQSLGSLYKRLFGQ 155 (177) T ss_pred HHHHHHHHHHHHHHCCCCCEEEECCCHHCCHHHHHHHHHHCCCCCCCCCEEEEEHHHHHHH-----CCCHHHHHHHHCCC T ss_conf 7999999999996267786799648512379999999998699899898899860764550-----69999999997599 Q ss_pred CCCCCCCCCCCCCCCHHHCCHHHHHHHHHHHHHHHHHHH Q ss_conf 422335654322210000001233332221111124567 Q gi|254780277|r 516 TRKEILKSRKSSIPIDKISDSQVQEHAIENSNVILQLWL 554 (976) Q Consensus 516 ~~~e~~~~~k~~~~~~~i~~e~~~~Yaa~Da~~t~~L~~ 554 (976) T Consensus 156 ~~~-------------------~aHRAl~Da~at~~vfl 175 (177) T cd06136 156 EPK-------------------NSHTAEGDVLALLKCAL 175 (177) T ss_pred CCC-------------------CCCCCHHHHHHHHHHHC T ss_conf 998-------------------77784899999999975

HHsearch alignment for GI: 254780277 and conserved domain: cd06136