Conserved Protein Domain Family
GH20_hexosaminidase

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cd02742: GH20_hexosaminidase 
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Beta-N-acetylhexosaminidases of glycosyl hydrolase family 20 (GH20) catalyze the removal of beta-1,4-linked N-acetyl-D-hexosamine residues from the non-reducing ends of N-acetyl-beta-D-hexosaminides including N-acetylglucosides and N-acetylgalactosides. These enzymes are broadly distributed in microorganisms, plants and animals, and play roles in various key physiological and pathological processes. These processes include cell structural integrity, energy storage, cellular signaling, fertilization, pathogen defense, viral penetration, the development of carcinomas, inflammatory events and lysosomal storage disorders. The GH20 enzymes include the eukaryotic beta-N-acetylhexosaminidases A and B, the bacterial chitobiases, dispersin B, and lacto-N-biosidase. The GH20 hexosaminidases are thought to act via a catalytic mechanism in which the catalytic nucleophile is not provided by the solvent or the enzyme, but by the substrate itself.
Statistics
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PSSM-Id: 119331
View PSSM: cd02742
Aligned: 11 rows
Threshold Bit Score: 309.365
Threshold Setting Gi: 169791634
Created: 13-Dec-2003
Updated: 17-Jan-2013
Structure
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Program:
Drawing:
Aligned Rows:
 
active site
Conserved site includes 8 residues -Click on image for an interactive view with Cn3D
Feature 1:active site [active site]
Evidence:
  • Structure:1YHT_A; Aggregatibacter actinomycetemcomitans dispersin B binds glycerol and acetic acid.
    View structure with Cn3D
  • Structure:1NP0_A; Homo sapiens Lysosomal Beta-Hexosaminidase isoform B (HexB) beta subunit, binds an intermediate analog NAG-Thiazoline (N-acetyl-beta-D-glucosamine-thiazoline).
    View structure with Cn3D
  • Structure:1C7T_A; Serratia marcescens chitobiase binds Di- N Acetyl-D-Glucosamine, contacts at 4A.
    View structure with Cn3D
  • Structure:1M01_A; Streptomyces plicatus Beta-hexosaminidase bound with product (GlcNAc), contacts at 3.5A. N-acetyl-D-glucosamine
    View structure with Cn3D
  • Comment:For 1M01_A, the most C-terminal active site Asp residue plays a critical role in substrate-assisted catalysis by orienting the 2-acetamido group and stabilizing the transition state.
  • Structure:2GK1_A/B; Homo sapiens Lysosomal Beta-Hexosaminidase isoform A (HexA), alpha and beta subunits each bind an intermediate analog NAG-Thiazoline (N-acetyl-beta-D-glucosamine-thiazoline), contacts at 4 A.
    View structure with Cn3D
  • Comment:there are two active sites in the HexA heterodimer, one in the alpha subunit, one in the beta subunit. A Tyr residue from the beta subunit is found in the active site of the alpha subunit and vice versa.

Sequence Alignment
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Format: Row Display: Color Bits: Type Selection:
                         10        20        30        40        50        60        70        80
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
Feature 1                 #                                                                      
1M01_A       159 WRSAMLDVSR-HFFGVDEVKRYIDRVARYKYNKLHLHLsddqgwRIAIDSWprlatyggs---------------tevgg 222
1NP0_B       153 HRGILIDTSR-HYLPVKIILKTLDAMAFNKFNVLHWHIvddqsfPYQSITFpelsnkg--------------------sy 211
1C7T_A       313 YRGIFLDVAR-NFHKKDAVLRLLDQMAAYKLNKFHFHLsddegwRIEIPGLpeltevggqrchdlsettcllpqygqgpd 391
2EPL_X        86 DLAYMADCSRnAVLNLSSAKKMIEVLALMGYSTFELYMe----dTYEIENQpyfg------------------------- 136
1YHT_A        18 QTGLMLDIAR-HFYSPEVIKSFIDTISLSGGNFLHLHFsdhenyAIESHLLnqraenavqgkd----------giyinpy 86
gi 187736406 126 IRCFMHDAGR-HFRTVETLKADIDEMARLKINAFHWHLtdypawRIQCKKYpvlndpskr----------------iqgr 188
gi 187734905 170 LRGIMLDVGR-YYMSPALIKEVMRRLSRYKINTLHLHLtddpawRLEVKKYpaltdgafh----------------wksr 232
gi 29345866  147 IRGFMQDVGR-SYLSLEELKREIAILSRFKINTFHWHLtenqawRLESKIFpmlndstn------------------mtr 207
gi 54308461  168 WRGALIDTSR-HFIPVDVIKRQIDGLASAKFNTFHWHLtddqgwRIESLAYpnlhek----------------------g 224
2GK1_A       147 HRGLLLDTSR-HYLPLSSILDTLDVMAYNKLNVFHWHLvddpsfPYESFTFpelmrkg-------------------syn 206
2GK1_B       153 HRGILIDTSR-HYLPVKIILKTLDAMAFNKFNVLHWHIvddqsfPYQSITFpelsnkg--------------------sy 211
                         90       100       110       120       130       140       150       160
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
Feature 1                                         #                                              
1M01_A       223 gpggYYTKAEYKEIVRYAASRHLEVVPEIDMPGHTNAALAsyaelncdgvap-------------------plytgtkvg 283
1NP0_B       212 slshVYTPNDVRMVIEYARLRGIRVLPEFDTPGHTLSWGKgqkdlltpcys----------------------rqnklds 269
1C7T_A       392 vyggFFSRQDYIDIIKYAQARQIEVIPEIDMPAHARAAVVsmearykklhaagkeqeanefrlvdqtdtsnttsvqffnr 471
2EPL_X       137 yfrgRYTVAELQEIEDYAADFDMSFVPCIQTLAHLSAFVKwgikevqe----------------------------lrdv 188
1YHT_A        87 tgkpFLSYRQLDDIKAYAKAKGIELIPELDSPNHMTAIFKlvqkdrgvkyl---------------------qglksrqv 145
gi 187736406 189 dvngTYSYDQIRDLFRYARERHVQIIPEIDMPGHSTYFKNcf-------------------------------------- 230
gi 187734905 233 lpgrFYTQAQLKDLTDYCARLNIQVIPEIDMPGHSQPFARam-------------------------------------- 274
gi 29345866  208 magkYYTLEEARELTEFCKAHQVLLIPEIDMPGHSAAFIRtf-------------------------------------- 249
gi 54308461  225 sdglYYTREQMKDVVAYAKNLGIRVIPEVDLPGHASAIAAaypelmtevkey-------------------kierkwgvh 285
2GK1_A       207 pvthIYTAQDVKEVIEYARLRGIRVLAEFDTPGHTLSWGPgipglltpcys----------------------gsepsgt 264
2GK1_B       212 slshVYTPNDVRMVIEYARLRGIRVLPEFDTPGHTLSWGKgqkdlltpcys----------------------rqnklds 269
                        170       180       190       200       210       220       230       240
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
Feature 1                                                ##                                      
1M01_A       284 fssLCVDKDVTYDFVDDVIGELAAlt-----pgRYLHIGGDEahs----------------------------------- 323
1NP0_B       270 fgpINPTLNTTYSFLTTFFKEISEvf-----pdQFIHLGGDEvefkcwesnpkiq------------------------- 319
1C7T_A       472 qsyLNPCLDSSQRFVDKVIGEIAQmhkeagqpiKTWHFGGDDaknirlgagytdkakpepgkgiidqsnedkpwaksqvc 551
2EPL_X       189 ediLLIGEEKVYDLIEGMFQTMAHlh------tRKINIGMDEahlvglgry----------------------------- 233
1YHT_A       146 ddeIDITNADSITFMQSLMSEVIDifg---dtsQHFHIGGDEfgys---------------------------------- 188
gi 187736406 231 --gFPMHDPRGINILEELLEEFCReipa--emsPYLHIGADEi------------------------------------- 269
gi 187734905 275 --kTGMQTEKGVSILKDVVDEAVSlf-----pgRFFHMGSDEa------------------------------------- 310
gi 29345866  250 --rHDMQSPEGMKILKLLLDEICEtf-----dvPYLHIGTDEv------------------------------------- 285
gi 54308461  286 eplLDPTKPEVYTFIDKIIGEVAElf-----pdEYIHIGGDEvnpkqwneskav-------------------------- 334
2GK1_A       265 fgpVNPSLNNTYEFMSTFFLEVSSvf-----pdFYLHLGGDEvdftcwksnpeiq------------------------- 314
2GK1_B       270 fgpINPTLNTTYSFLTTFFKEISEvf-----pdQFIHLGGDEvefkcwesnpkiq------------------------- 319
                        250       260       270       280       290       300       310       320
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
Feature 1                                             #                                       #  
1M01_A       324 ----------tpKADFVAFMKRVQPIVAKyg-kTVVGWHQlagae-----------------------pvegALVQYWgl 369
1NP0_B       320 dfmrqkgfgtdfKKLESFYIQKVLDIIATin-kGSIVWQEvfddka---------------------klapgTIVEVWkd 377
1C7T_A       552 qtmikegkvadmEHLPSYFGQEVSKLVKAhgidRMQAWQDglkdaess-----------------kafatsrVGVNFWdt 614
2EPL_X       234 ---likhgfqnrSLLMCQHLERVLDIADKyg-fNCQMWSDmffklmsadgqydrdveipeetrvyldrlkerVTLVYWdy 309
1YHT_A       189 ---------vesNHEFITYANKLSYFLEKkg-lKTRMWNDglikntf-------------------eqinpnIEITYWsy 239
gi 187736406 270 -----------rIPNGKQFADRMAAKVKSlg-rQPIQWAGnndlp-----------------------vsgdSYAQLWnd 314
gi 187734905 311 ------------HISMKDFIPRMAEHIRGkg-kEVVVWSPggph-------------------------dkdSVLMCWge 352
gi 29345866  286 ------------HFTNPQFVPEMVAYVRDkg-kKVISWNPgwkyk-----------------------ageiDMMQLWsy 329
gi 54308461  335 qtfmaekglkdaLELHAFFNQEVEEILKKhd-rKMIGWDEtyhpd-----------------------lpksIVIQSWrg 390
2GK1_A       315 dfmrkkgfgedfKQLESFYIQTLLDIVSSyg-kGYVVWQEvfdnkv---------------------kiqpdTIIQVWre 372
2GK1_B       320 dfmrqkgfgtdfKKLESFYIQKVLDIIATin-kGSIVWQEvfddka---------------------klapgTIVEVWkd 377
                        330       340       350       360       370       380       390       400
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
Feature 1                                                                                        
1M01_A       370 drtg---------daekaeVAEAARNGTGLILSpadrtyldmkytk--dtplglswagyveVQRSYDwdpagyl------ 432
1NP0_B       378 sa-------------ypeeLSRVTASGFPVILSapwyldl---------------isygqdWRKYYKvepldfgg----- 424
1C7T_A       615 lyw-----------ggfdsVNDWANKGYEVVVSnpdyvymdfpyevnpdergyywgtrfsdERKVFSfapdnmpqnaets 683
2EPL_X       310 yqdse--------ekynrnFQNHHKISQDIAFAggawkwig-------------ftphnhfSRLVAIeanka-------- 360
1YHT_A       240 dgdtqdkneaaerrdmrvsLPELLAKGFTVLNYnsyylyivpka------sptfsqdaafaAKDVIKnwdlgvwdgrn-- 311
gi 187736406 315 en--------------svgLPDPARQKNPYFDStagyvns--------------fdpgilvRRNFFRqpcgta------- 359
gi 187734905 353 -----------------neAGARMDKNMKRIDSngfyidw---------------adsqsgVYQVFFqqpcev------- 393
gi 29345866  330 rg-------------kaqqGIPAIDSRFHYLNHfdtfgd-----------------iialyNSRIYNadmg--------- 370
gi 54308461  391 h----------------dsLGESANDGYQGILStgyyi------------------dqaqpAAMHYRndpmpkplqvdde 436
2GK1_A       373 dipv----------nymkeLELVTKAGFRALLSapwylnr---------------isygpdWKDFYVveplafeg----- 422
2GK1_B       378 sa-------------ypeeLSRVTASGFPVILSapwyldl---------------isygqdWRKYYKvepldfgg----- 424
                        410       420       430       440       450       460       470       480
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
Feature 1                                                                                        
1M01_A           --------------------------------------------------------------------------------
1NP0_B           --------------------------------------------------------------------------------
1C7T_A       684 vdr----------------------------------------------------------------------------- 686
2EPL_X           --------------------------------------------------------------------------------
1YHT_A           --------------------------------------------------------------------------------
gi 187736406     --------------------------------------------------------------------------------
gi 187734905     --------------------------------------------------------------------------------
gi 29345866      --------------------------------------------------------------------------------
gi 54308461  437 vhtdeswetwqfeaprkrgsavtgtftlitakdgtrrgfidyksrsrravfdiettqgitsfwmdswmgqtkprvelqgg 516
2GK1_A           --------------------------------------------------------------------------------
2GK1_B           --------------------------------------------------------------------------------
                        490       500       510       520       530       540       550       560
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
Feature 1                                                              # #                       
1M01_A       433 ---------------------------------------pgapadaVRGVEAPLWTEtlsdpd---qldymAFPRLPGVA 470
1NP0_B       425 ---------------------------------------tqkqkqlFIGGEACLWGEyvdat----nltprLWPRASAVG 461
1C7T_A       687 -------------------------------dgnhfnaksdkpwpgAYGLSAQLWSEtqrtdp---qmeymIFPRALSVA 732
2EPL_X       361 -----------------------------------------crknqVKEVIVTGWGDngget-----sqfsVLPALQIWA 394
1YHT_A       312 ------------------------------------tknrvqntheIAGAALSIWGEdakalkd-etiqknTKSLLEAVI 354
gi 187736406 360 -----------------------------------------rgnnhSLGVIQCLWPDtrvenkknipvqspQWPAMFAMA 398
gi 187734905 394 ----------------------------------------pqgddkALGAIMPVWCDgnlsserrvleqypFYPCALTFA 433
gi 29345866  371 -------------------------------------------sddLAGVIMGIWNDrlidkewnmvlennFYPNMLAIA 407
gi 54308461  517 kltghmvvgnaqyvmtgqkiagndiqnsqyptapypvalkkeqehlILGGEVTLWAEnvkdd----tidlrMWPRSYVIA 592
2GK1_A       423 ---------------------------------------tpeqkalVIGGEACMWGEyvdnt----nlvprLWPRAGAVA 459
2GK1_B       425 ---------------------------------------tqkqkqlFIGGEACLWGEyvdat----nltprLWPRASAVG 461

                 ....*
Feature 1             
1M01_A       471 ELGWS 475
1NP0_B       462 ERLWS 466
1C7T_A       733 ERSWH 737
2EPL_X       395 ELAYR 399
1YHT_A       355 HKTNG 359
gi 187736406 399 ERSWK 403
gi 187734905 434 ERVWR 438
gi 29345866  408 ERSWR 412
gi 54308461  593 ERLWS 597
2GK1_A       460 ERLWS 464
2GK1_B       462 ERLWS 466

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