Conserved Protein Domain Family
CBM20_DPE2_repeat1

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cd05815: CBM20_DPE2_repeat1 
Disproportionating enzyme 2 (DPE2), N-terminal CBM20 (carbohydrate-binding module, family 20) domain, repeat 1. DPE2 is a transglucosidase that is essential for the cytosolic metabolism of maltose in plant leaves at night. Maltose is an intermediate on the pathway from starch to sucrose and DPE2 is thought to metabolize the maltose that is exported from the chloroplast. DPE2 has two N-terminal CBM20 starch binding domains as well as a C-terminal amylomaltase (4-alpha-glucanotransferase) catalytic domain. DPE1, the plastid version of this enzyme, has a transglucosidase domain that is similar to that of DPE2 but lacks the N-terminal carbohydrate-binding domains. The CBM20 domain is found in a large number of starch degrading enzymes including alpha-amylase, beta-amylase, glucoamylase, and CGTase (cyclodextrin glucanotransferase). CBM20 is also present in proteins that have a regulatory role in starch metabolism in plants (e.g. alpha-amylase) or glycogen metabolism in mammals (e.g. laforin). CBM20 folds as an antiparallel beta-barrel structure with two starch binding sites. These two sites are thought to differ functionally with site 1 acting as the initial starch recognition site and site 2 involved in the specific recognition of appropriate regions of starch.
Statistics
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PSSM-Id: 99889
View PSSM: cd05815
Aligned: 6 rows
Threshold Bit Score: 166.851
Threshold Setting Gi: 159486300
Created: 14-Jan-2008
Updated: 2-Oct-2020
Structure
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Aligned Rows:
 
starch bindingstarch binding
Feature 1:starch binding site 1 [chemical binding site]
Evidence:
  • Comment:Based on the binding of substrates to the starch binding site 1 of other family members.
  • Comment:Site 1 is small relative to site 2 and exhibits minimal structural changes upon ligand binding. It acts as an initial starch recognition site.
  • Citation:PMID 9195884
  • Citation:PMID 8672460

Sequence Alignment
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Format: Row Display: Color Bits: Type Selection:
Feature 1                                    #                                 #             ##   
NP_181616      20 SISFWIPYFTHWGESLLVCGSAPGLGSGNVKKGLLLKPSQQDDQLIWSGSVSVPPGFSSDYCYYVVDd-sKSVLRSEFGM 98   thale cress
AAR99599       10 KVSFRIPYYTQWGQNLLICGSDRLLGSWNVKKGLLLKPSHQGEVLVWSGSIPVPPGYQSEYSYYVVDd-rRNILRWEVGK 88   potato
EAZ40984       19 TLVFKLPYYTQWGQSLLIAGSEPALGSWNVKQGLSLSPVHQGNELIWSGRVSVATGFTCQYNYYVVDd-nKNVLRSESGE 97   Japanese rice
EDQ55980       21 NILFKLPYNTQWGQNLMIIGSDALLGAWVVEKGQRLMPRQEGDVLVWEVSISVSERFETEYNYVVVDd-rFRGLRRESGA 99   Physcomitrell...
XP_001701179   10 TLHFSVAYPTQWGQCILLAGSGALLGGLEWSKARQLSCTNDKDLIVWEATIVLPWKPSYTYKYALDDtsgPSVHGNWIIE 89   Chlamydomonas...
CAO18259       17 YVSFRLPYYTHWGQSLLVCGSEPVLGSWDVKKGLLLKPVHRGDELIWCGDVAVPGGFGCEYSYYVVNd-dRKALRWEAGK 95   Vitis vinifera
Feature 1               #                     
NP_181616      99 ------KRKLVVPETLTGGESVHLRDLW 120  thale cress
AAR99599       89 ------KRKLLLPDGLQDGQSLELRDLW 110  potato
EAZ40984       98 ------KRKLVLPEGVQDGDVVEIRDWW 119  Japanese rice
EDQ55980      100 ------RRVLSLPEGLSNGATVEVHDLW 121  Physcomitrella patens subsp. patens
XP_001701179   90 kedaagERTVWLPEGLQGGELVEVVDSW 117  Chlamydomonas reinhardtii
CAO18259       96 ------KRKLVLPEVIEHGEVVELHDLW 117  Vitis vinifera

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