ID IABF_GEOSE Reviewed; 502 AA. AC Q9XBQ3; DT 26-JUL-2002, integrated into UniProtKB/Swiss-Prot. DT 23-JAN-2007, sequence version 4. DT 03-MAY-2023, entry version 89. DE RecName: Full=Intracellular exo-alpha-(1->5)-L-arabinofuranosidase; DE Short=ABF; DE EC=3.2.1.55; DE AltName: Full=Intracellular arabinan exo-alpha-(1->5)-L-arabinosidase; DE Short=Arabinosidase; GN Name=abfA; OS Geobacillus stearothermophilus (Bacillus stearothermophilus). OC Bacteria; Bacillota; Bacilli; Bacillales; Bacillaceae; Geobacillus. OX NCBI_TaxID=1422; RN [1] RP NUCLEOTIDE SEQUENCE [GENOMIC DNA]. RC STRAIN=T-6 / NCIMB 40222; RA Gilead-Gropper S., Gat O., Alchanati I., Yaron S., Bren A., Shoham Y.; RL Submitted (NOV-2001) to the EMBL/GenBank/DDBJ databases. RN [2] RP PROTEIN SEQUENCE OF 2-51, FUNCTION, ACTIVITY REGULATION, BIOPHYSICOCHEMICAL RP PROPERTIES, INDUCTION, AND SUBUNIT. RC STRAIN=T-6 / NCIMB 40222; RX PubMed=7887599; DOI=10.1128/aem.61.1.170-174.1995; RA Gilead S., Shoham Y.; RT "Purification and characterization of alpha-L-arabinofuranosidase from RT Bacillus stearothermophilus T-6."; RL Appl. Environ. Microbiol. 61:170-174(1995). RN [3] RP FUNCTION, MUTAGENESIS OF GLU-175, ACTIVE SITE, BIOPHYSICOCHEMICAL RP PROPERTIES, AND REACTION MECHANISM. RX PubMed=11943144; DOI=10.1016/s0014-5793(02)02343-8; RA Shallom D., Belakhov V., Solomon D., Gilead-Gropper S., Baasov T., RA Shoham G., Shoham Y.; RT "The identification of the acid-base catalyst of alpha-arabinofuranosidase RT from Geobacillus stearothermophilus T-6, a family 51 glycoside hydrolase."; RL FEBS Lett. 514:163-167(2002). RN [4] RP FUNCTION, CATALYTIC ACTIVITY, MUTAGENESIS OF GLU-175 AND GLU-294, ACTIVE RP SITE, BIOPHYSICOCHEMICAL PROPERTIES, AND REACTION MECHANISM. RX PubMed=12221104; DOI=10.1074/jbc.m208285200; RA Shallom D., Belakhov V., Solomon D., Shoham G., Baasov T., Shoham Y.; RT "Detailed kinetic analysis and identification of the nucleophile in alpha- RT L-arabinofuranosidase from Geobacillus stearothermophilus T-6, a family 51 RT glycoside hydrolase."; RL J. Biol. Chem. 277:43667-43673(2002). RN [5] RP SUBUNIT. RX PubMed=12777810; DOI=10.1107/s0907444903004037; RA Hovel K., Shallom D., Niefind K., Baasov T., Shoham G., Shoham Y., RA Schomburg D.; RT "Crystallization and preliminary X-ray analysis of a family 51 glycoside RT hydrolase, the alpha-l-arabinofuranosidase from Geobacillus RT stearothermophilus T-6."; RL Acta Crystallogr. D 59:913-915(2003). RN [6] RP X-RAY CRYSTALLOGRAPHY (2.0 ANGSTROMS) OF MUTANT ALA-175 IN COMPLEX WITH RP SUBSTRATE ANALOGS, FUNCTION, CATALYTIC ACTIVITY, MUTAGENESIS OF GLU-175, RP REACTION MECHANISM, ACTIVE SITE, BIOPHYSICOCHEMICAL PROPERTIES, SUBSTRATE RP SPECIFICITY, AND SUBUNIT. RX PubMed=14517232; DOI=10.1093/emboj/cdg494; RA Hovel K., Shallom D., Niefind K., Belakhov V., Shoham G., Baasov T., RA Shoham Y., Schomburg D.; RT "Crystal structure and snapshots along the reaction pathway of a family 51 RT alpha-L-arabinofuranosidase."; RL EMBO J. 22:4922-4932(2003). CC -!- FUNCTION: Involved in the degradation of arabinan and is a key enzyme CC in the complete degradation of the plant cell wall. Catalyzes the CC cleavage of terminal alpha-(1->5)-arabinofuranosyl bonds in different CC hemicellulosic homopolysaccharides (branched and debranched arabinans). CC It acts preferentially on aryl-alpha-L-arabinofuranosides, and is much CC less effective on aryl-beta-D-xylopyranosides. CC {ECO:0000269|PubMed:11943144, ECO:0000269|PubMed:12221104, CC ECO:0000269|PubMed:14517232, ECO:0000269|PubMed:7887599}. CC -!- CATALYTIC ACTIVITY: CC Reaction=Hydrolysis of terminal non-reducing alpha-L-arabinofuranoside CC residues in alpha-L-arabinosides.; EC=3.2.1.55; CC Evidence={ECO:0000269|PubMed:12221104, ECO:0000269|PubMed:14517232}; CC -!- ACTIVITY REGULATION: Strongly inhibited by Hg(2+). CC {ECO:0000269|PubMed:7887599}. CC -!- BIOPHYSICOCHEMICAL PROPERTIES: CC Kinetic parameters: CC KM=0.35 mM for 2,5-dinitro-arabinofuranosyl CC {ECO:0000269|PubMed:11943144, ECO:0000269|PubMed:12221104, CC ECO:0000269|PubMed:14517232, ECO:0000269|PubMed:7887599}; CC KM=0.42 mM for p-nitrophenyl alpha-L-arabinofuranoside (pNP-Araf) (at CC 60 degrees Celsius and at pH 6) {ECO:0000269|PubMed:11943144, CC ECO:0000269|PubMed:12221104, ECO:0000269|PubMed:14517232, CC ECO:0000269|PubMed:7887599}; CC KM=0.53 mM for 3,4-dinitro-arabinofuranosyl CC {ECO:0000269|PubMed:11943144, ECO:0000269|PubMed:12221104, CC ECO:0000269|PubMed:14517232, ECO:0000269|PubMed:7887599}; CC KM=0.65 mM for 4-nitro-arabinofuranosyl {ECO:0000269|PubMed:11943144, CC ECO:0000269|PubMed:12221104, ECO:0000269|PubMed:14517232, CC ECO:0000269|PubMed:7887599}; CC KM=4.4 mM for 3,4-dinitro-xylopyranosyl {ECO:0000269|PubMed:11943144, CC ECO:0000269|PubMed:12221104, ECO:0000269|PubMed:14517232, CC ECO:0000269|PubMed:7887599}; CC KM=8 mM for 2,5-dinitro-xylopyranosyl {ECO:0000269|PubMed:11943144, CC ECO:0000269|PubMed:12221104, ECO:0000269|PubMed:14517232, CC ECO:0000269|PubMed:7887599}; CC KM=15.3 mM for 2-nitro-xylopyranosyl {ECO:0000269|PubMed:11943144, CC ECO:0000269|PubMed:12221104, ECO:0000269|PubMed:14517232, CC ECO:0000269|PubMed:7887599}; CC Vmax=749 umol/min/mg enzyme (at 60 degrees Celsius and at pH 6) CC {ECO:0000269|PubMed:11943144, ECO:0000269|PubMed:12221104, CC ECO:0000269|PubMed:14517232, ECO:0000269|PubMed:7887599}; CC Note=Apparently, AbfA can accommodate xylopyranose in the active CC site, but without the necessary distortion required for the efficient CC catalysis of six-membered rings. This explains in part its lower CC specificity towards the xylopyranosidic substrates CC (PubMed:14517232).; CC pH dependence: CC Optimum pH is 5.5-6.0. {ECO:0000269|PubMed:11943144, CC ECO:0000269|PubMed:12221104, ECO:0000269|PubMed:14517232, CC ECO:0000269|PubMed:7887599}; CC Temperature dependence: CC Optimum temperature is 70 degrees Celsius. CC {ECO:0000269|PubMed:11943144, ECO:0000269|PubMed:12221104, CC ECO:0000269|PubMed:14517232, ECO:0000269|PubMed:7887599}; CC -!- PATHWAY: Glycan metabolism; L-arabinan degradation. CC -!- SUBUNIT: Homohexamer; trimer of dimers. {ECO:0000305|PubMed:12777810, CC ECO:0000305|PubMed:14517232, ECO:0000305|PubMed:7887599}. CC -!- SUBCELLULAR LOCATION: Cytoplasm {ECO:0000250}. CC -!- INDUCTION: Transcription is repressed by glucose and by the binding of CC AraR to the operon promoter. L-arabinose acts as an inducer by CC inhibiting the binding of AraR to the DNA, thus allowing expression of CC the gene (Probable). {ECO:0000305|PubMed:7887599}. CC -!- SIMILARITY: Belongs to the glycosyl hydrolase 51 family. {ECO:0000305}. CC --------------------------------------------------------------------------- CC Copyrighted by the UniProt Consortium, see https://www.uniprot.org/terms CC Distributed under the Creative Commons Attribution (CC BY 4.0) License CC --------------------------------------------------------------------------- DR EMBL; AF159625; AAD45520.2; -; Genomic_DNA. DR PDB; 1PZ2; X-ray; 2.00 A; A/B=1-502. DR PDB; 1PZ3; X-ray; 1.75 A; A/B=1-502. DR PDB; 1QW8; X-ray; 1.80 A; A/B=1-502. DR PDB; 1QW9; X-ray; 1.20 A; A/B=1-502. DR PDB; 6SXU; X-ray; 1.40 A; AAA/BBB=1-502. DR PDB; 6SXV; X-ray; 1.40 A; A/B=1-502. DR PDBsum; 1PZ2; -. DR PDBsum; 1PZ3; -. DR PDBsum; 1QW8; -. DR PDBsum; 1QW9; -. DR PDBsum; 6SXU; -. DR PDBsum; 6SXV; -. DR AlphaFoldDB; Q9XBQ3; -. DR SMR; Q9XBQ3; -. DR DrugBank; DB03196; 4-Nitrophenyl-Ara. DR DrugBank; DB03870; Ara-Alpha(1,3)-Xyl. DR CAZy; GH51; Glycoside Hydrolase Family 51. DR BRENDA; 3.2.1.55; 623. DR UniPathway; UPA00667; -. DR EvolutionaryTrace; Q9XBQ3; -. DR GO; GO:0005737; C:cytoplasm; IEA:UniProtKB-SubCell. DR GO; GO:0046556; F:alpha-L-arabinofuranosidase activity; IEA:UniProtKB-EC. DR GO; GO:0031222; P:arabinan catabolic process; IEA:UniProtKB-UniPathway. DR GO; GO:0046373; P:L-arabinose metabolic process; IEA:InterPro. DR Gene3D; 3.20.20.80; Glycosidases; 1. DR Gene3D; 2.60.40.1180; Golgi alpha-mannosidase II; 1. DR InterPro; IPR010720; Alpha-L-AF_C. DR InterPro; IPR013780; Glyco_hydro_b. DR InterPro; IPR017853; Glycoside_hydrolase_SF. DR PANTHER; PTHR43576:SF3; ALPHA-L-ARABINOFURANOSIDASE C; 1. DR PANTHER; PTHR43576; ALPHA-L-ARABINOFURANOSIDASE C-RELATED; 1. DR Pfam; PF06964; Alpha-L-AF_C; 1. DR SMART; SM00813; Alpha-L-AF_C; 1. DR SUPFAM; SSF51445; (Trans)glycosidases; 1. DR SUPFAM; SSF51011; Glycosyl hydrolase domain; 1. PE 1: Evidence at protein level; KW 3D-structure; Carbohydrate metabolism; Cytoplasm; KW Direct protein sequencing; Glycosidase; Hydrolase. FT INIT_MET 1 FT /note="Removed" FT /evidence="ECO:0000269|PubMed:7887599" FT CHAIN 2..502 FT /note="Intracellular exo-alpha-(1->5)-L- FT arabinofuranosidase" FT /id="PRO_0000057700" FT ACT_SITE 175 FT /note="Proton donor/acceptor" FT ACT_SITE 294 FT /note="Nucleophile" FT BINDING 29 FT /ligand="substrate" FT BINDING 74 FT /ligand="substrate" FT BINDING 174..175 FT /ligand="substrate" FT /evidence="ECO:0000250" FT BINDING 246 FT /ligand="substrate" FT BINDING 294 FT /ligand="substrate" FT BINDING 351 FT /ligand="substrate" FT /evidence="ECO:0000250" FT SITE 298 FT /note="Important for substrate recognition" FT /evidence="ECO:0000305" FT SITE 351 FT /note="Important for substrate recognition" FT /evidence="ECO:0000305" FT MUTAGEN 175 FT /note="E->A: Strongly reduced catalytic activity. Increases FT affinity for substrates. The mutant has an effect on the FT glycosylation step. The removal of the acid-base catalyst FT seems to have affected the ionization state of the FT nucleophile, elevating its pKa, reducing its acidity, and FT shifting the optimal pH to higher values." FT /evidence="ECO:0000269|PubMed:11943144, FT ECO:0000269|PubMed:12221104, ECO:0000269|PubMed:14517232" FT MUTAGEN 294 FT /note="E->A: Abolishes catalytic activity, but the binding FT affinity shows only a small change." FT /evidence="ECO:0000269|PubMed:12221104" FT STRAND 6..9 FT /evidence="ECO:0007829|PDB:1QW9" FT STRAND 14..18 FT /evidence="ECO:0007829|PDB:1QW9" FT HELIX 21..24 FT /evidence="ECO:0007829|PDB:1QW9" FT STRAND 25..27 FT /evidence="ECO:0007829|PDB:1QW9" FT TURN 37..39 FT /evidence="ECO:0007829|PDB:1QW9" FT STRAND 51..53 FT /evidence="ECO:0007829|PDB:1QW9" FT HELIX 54..62 FT /evidence="ECO:0007829|PDB:1QW9" FT STRAND 67..71 FT /evidence="ECO:0007829|PDB:1QW9" FT HELIX 74..78 FT /evidence="ECO:0007829|PDB:1QW9" FT HELIX 81..84 FT /evidence="ECO:0007829|PDB:1QW9" FT HELIX 88..90 FT /evidence="ECO:0007829|PDB:1QW9" FT STRAND 94..96 FT /evidence="ECO:0007829|PDB:1QW9" FT TURN 97..100 FT /evidence="ECO:0007829|PDB:1QW9" FT STRAND 101..103 FT /evidence="ECO:0007829|PDB:1QW9" FT HELIX 109..119 FT /evidence="ECO:0007829|PDB:1QW9" FT STRAND 122..127 FT /evidence="ECO:0007829|PDB:1QW9" FT HELIX 134..145 FT /evidence="ECO:0007829|PDB:1QW9" FT STRAND 148..150 FT /evidence="ECO:0007829|PDB:1QW9" FT HELIX 151..158 FT /evidence="ECO:0007829|PDB:1QW9" FT STRAND 169..174 FT /evidence="ECO:0007829|PDB:1QW9" FT HELIX 187..204 FT /evidence="ECO:0007829|PDB:1QW9" FT STRAND 209..212 FT /evidence="ECO:0007829|PDB:1QW9" FT TURN 221..224 FT /evidence="ECO:0007829|PDB:1QW9" FT HELIX 225..234 FT /evidence="ECO:0007829|PDB:1QW9" FT HELIX 235..237 FT /evidence="ECO:0007829|PDB:1QW9" FT STRAND 239..247 FT /evidence="ECO:0007829|PDB:1QW9" FT HELIX 254..258 FT /evidence="ECO:0007829|PDB:1QW9" FT HELIX 261..282 FT /evidence="ECO:0007829|PDB:1QW9" FT STRAND 289..297 FT /evidence="ECO:0007829|PDB:1QW9" FT HELIX 302..305 FT /evidence="ECO:0007829|PDB:1QW9" FT STRAND 312..314 FT /evidence="ECO:0007829|PDB:1QW9" FT HELIX 324..339 FT /evidence="ECO:0007829|PDB:1QW9" FT TURN 340..343 FT /evidence="ECO:0007829|PDB:1QW9" FT STRAND 344..350 FT /evidence="ECO:0007829|PDB:1QW9" FT STRAND 352..356 FT /evidence="ECO:0007829|PDB:1QW9" FT STRAND 358..361 FT /evidence="ECO:0007829|PDB:1QW9" FT STRAND 367..369 FT /evidence="ECO:0007829|PDB:1QW9" FT HELIX 373..382 FT /evidence="ECO:0007829|PDB:1QW9" FT STRAND 385..388 FT /evidence="ECO:0007829|PDB:1QW9" FT STRAND 391..393 FT /evidence="ECO:0007829|PDB:1QW9" FT STRAND 403..415 FT /evidence="ECO:0007829|PDB:1QW9" FT TURN 416..419 FT /evidence="ECO:0007829|PDB:1QW9" FT STRAND 420..427 FT /evidence="ECO:0007829|PDB:1QW9" FT STRAND 430..432 FT /evidence="ECO:0007829|PDB:1PZ3" FT STRAND 434..439 FT /evidence="ECO:0007829|PDB:1QW9" FT STRAND 447..454 FT /evidence="ECO:0007829|PDB:1QW9" FT STRAND 473..475 FT /evidence="ECO:0007829|PDB:1PZ3" FT STRAND 479..481 FT /evidence="ECO:0007829|PDB:1QW9" FT STRAND 484..489 FT /evidence="ECO:0007829|PDB:1QW9" FT STRAND 491..500 FT /evidence="ECO:0007829|PDB:1QW9" SQ SEQUENCE 502 AA; 57212 MW; 37C048AE29DBB230 CRC64; MATKKATMII EKDFKIAEID KRIYGSFIEH LGRAVYGGIY EPGHPQADEN GFRQDVIELV KELQVPIIRY PGGNFVSGYN WEDGVGPKEQ RPRRLDLAWK SVETNEIGLN EFMDWAKMVG AEVNMAVNLG TRGIDAARNL VEYCNHPSGS YYSDLRIAHG YKEPHKIKTW CLGNEMDGPW QIGHKTAVEY GRIACEAAKV MKWVDPTIEL VVCGSSNRNM PTFAEWEATV LDHTYDHVDY ISLHQYYGNR DNDTANYLAL SLEMDDFIRS VVAIADYVKA KKRSKKTIHL SFDEWNVWYH SNEADKLIEP WTVAPPLLED IYNFEDALLV GCMLITLMKH ADRVKIACLA QLVNVIAPIM TEKNGPAWKQ TIYYPFMHAS VYGRGVALHP VISSPKYDSK DFTDVPYLES IAVYNEEKEE VTIFAVNRDM EDALLLECDV RSFEDYRVIE HIVLEHDNVK QTNSAQSSPV VPHRNGDAQL SDRKVSATLP KLSWNVIRLG KR //