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: 17-Jan-2013
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:
                          10        20        30        40        50        60        70        80
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
Feature 1                                    #                                 #             ##   
gi 42569818    20 SISFWIPYFTHWGESLLVCGSAPGLGSGNVKKGLLLKPSQQDDQLIWSGSVSVPPGFSSDYCYYVVDd-sKSVLRSEFGM 98
gi 41176619    10 KVSFRIPYYTQWGQNLLICGSDRLLGSWNVKKGLLLKPSHQGEVLVWSGSIPVPPGYQSEYSYYVVDd-rRNILRWEVGK 88
gi 125601408   19 TLVFKLPYYTQWGQSLLIAGSEPALGSWNVKQGLSLSPVHQGNELIWSGRVSVATGFTCQYNYYVVDd-nKNVLRSESGE 97
gi 162669392   21 NILFKLPYNTQWGQNLMIIGSDALLGAWVVEKGQRLMPRQEGDVLVWEVSISVSERFETEYNYVVVDd-rFRGLRRESGA 99
gi 159486300   10 TLHFSVAYPTQWGQCILLAGSGALLGGLEWSKARQLSCTNDKDLIVWEATIVLPWKPSYTYKYALDDtsgPSVHGNWIIE 89
gi 157347622   17 YVSFRLPYYTHWGQSLLVCGSEPVLGSWDVKKGLLLKPVHRGDELIWCGDVAVPGGFGCEYSYYVVNd-dRKALRWEAGK 95
                          90       100
                  ....*....|....*....|....*...
Feature 1               #                     
gi 42569818    99 ------KRKLVVPETLTGGESVHLRDLW 120
gi 41176619    89 ------KRKLLLPDGLQDGQSLELRDLW 110
gi 125601408   98 ------KRKLVLPEGVQDGDVVEIRDWW 119
gi 162669392  100 ------RRVLSLPEGLSNGATVEVHDLW 121
gi 159486300   90 kedaagERTVWLPEGLQGGELVEVVDSW 117
gi 157347622   96 ------KRKLVLPEVIEHGEVVELHDLW 117

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