1ITC,1VEP


Conserved Protein Domain Family
CBM20_beta_amylase

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cd05809: CBM20_beta_amylase 
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Beta-amylase, C-terminal CBM20 (carbohydrate-binding module, family 20) domain. Beta-amylase has, in addition to its C-terminal CBM20 domain, an N-terminal catalytic domain belonging to glycosyl hydrolase family 14, which hydrolyzes the alpha-1,4-glucosidic bonds of starch, yielding beta-maltose from the nonreducing end of the substrate. Beta-amylase is found in both plants and microorganisms, however the plant members lack a C-terminal CBM20 domain and are not included in this group. 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: 99884
View PSSM: cd05809
Aligned: 5 rows
Threshold Bit Score: 130.828
Threshold Setting Gi: 113785
Created: 10-Sep-2007
Updated: 17-Jan-2013
Structure
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Program:
Drawing:
Aligned Rows:
 
starch-bindingstarch-binding
Conserved site includes 4 residues -Click on image for an interactive view with Cn3D
Feature 1:starch-binding site 1 [chemical binding site]
Evidence:
  • Structure:1ITC_A; The CBM20 domain (domain C) starch binding site 1 of Bacillus cereus beta-amylase binds a trisaccharide portion of maltopentaose; defined at 4A contacts.
    View structure with Cn3D

Sequence Alignment
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Format: Row Display: Color Bits: Type Selection:
Feature 1                                        #                                  #            #
1ITC_A        418 TPVMQTIVVKNVPTTIGDTVYITGNRAELGSWDTK--QYPIQLYYDshsNDWRGNVVLPAERNIEFKAFIKSKDGtVKSW 495 Bacillus cereus
1VEP_A        418 TPVMQTIVVKNVPTTIGDTVYITGNRAELGSWDTK--QYPIQLYYDshsNDWRGNVVLPAERNIEFKAFIKSKDGtVKSW 495 Bacillus cereus
CAB61483      448 TPLAQTVVVKNAPTALGETVYIVGDRAELGQWDTS--IYPIKLTYNsstADWRGTVHFPASQNVQFKAIVKRADGsLKAW 525 Bacillus megat...
tigr:CLC_1245 447 KPVPVTFTVNNVNLESDENLYLTGSRWEMANWSTE--FYPLQFKNNn--GSYTITTHLAEGHNYEFKAIKKNNNG-NVIW 521 Clostridium bo...
P19584        452 GTIPVTFTINNATTYYGQNVYIVGSTSDLGNWNTTyaRGPASCPNY---PTWTITLNLLPGEQIQFKAVKIDSSG-NVTW 527 Thermoanaeroba...
Feature 1            #                  
1ITC_A        496 QTIQQSWNpVPL-KTTSHTSSW 516 Bacillus cereus
1VEP_A        496 QTIQQSWNpVPL-KTTSHTSSW 516 Bacillus cereus
CAB61483      526 QPSQQYWS-VPS-TTTTYTDNW 545 Bacillus megaterium
tigr:CLC_1245 522 QGGYNKFYnVPK-GGDSYTWSW 542 Clostridium botulinum A str. Hall
P19584        528 EGGSNHTYtVPTsGTGSVTITW 549 Thermoanaerobacterium thermosulfurigenes

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