ID   XTH33_ARATH             Reviewed;         310 AA.
AC   Q8LC45; Q9XIJ7;
DT   28-NOV-2003, integrated into UniProtKB/Swiss-Prot.
DT   28-NOV-2003, sequence version 2.
DT   04-NOV-2026, entry version 156.
DE   RecName: Full=Probable xyloglucan endotransglucosylase/hydrolase protein 33 {ECO:0000303|PubMed:12514239};
DE            Short=At-XTH33 {ECO:0000303|PubMed:12514239};
DE            Short=XTH-33 {ECO:0000303|PubMed:12514239};
DE            EC=2.4.1.207 {ECO:0000250|UniProtKB:Q38857};
DE   Flags: Precursor;
GN   Name=XTH33 {ECO:0000303|PubMed:12514239};
GN   OrderedLocusNames=At1g10550 {ECO:0000312|Araport:AT1G10550};
GN   ORFNames=T10O24.17 {ECO:0000312|EMBL:AAD39577.1};
OS   Arabidopsis thaliana (Mouse-ear cress).
OC   Eukaryota; Viridiplantae; Streptophyta; Embryophyta; Tracheophyta;
OC   Spermatophyta; Magnoliopsida; eudicotyledons; Gunneridae; Pentapetalae;
OC   rosids; malvids; Brassicales; Brassicaceae; Camelineae; Arabidopsis.
OX   NCBI_TaxID=3702;
RN   [1]
RP   NUCLEOTIDE SEQUENCE [LARGE SCALE GENOMIC DNA].
RC   STRAIN=cv. Columbia;
RX   PubMed=11130712; DOI=10.1038/35048500;
RA   Theologis A., Ecker J.R., Palm C.J., Federspiel N.A., Kaul S., White O.,
RA   Alonso J., Altafi H., Araujo R., Bowman C.L., Brooks S.Y., Buehler E.,
RA   Chan A., Chao Q., Chen H., Cheuk R.F., Chin C.W., Chung M.K., Conn L.,
RA   Conway A.B., Conway A.R., Creasy T.H., Dewar K., Dunn P., Etgu P.,
RA   Feldblyum T.V., Feng J.-D., Fong B., Fujii C.Y., Gill J.E., Goldsmith A.D.,
RA   Haas B., Hansen N.F., Hughes B., Huizar L., Hunter J.L., Jenkins J.,
RA   Johnson-Hopson C., Khan S., Khaykin E., Kim C.J., Koo H.L.,
RA   Kremenetskaia I., Kurtz D.B., Kwan A., Lam B., Langin-Hooper S., Lee A.,
RA   Lee J.M., Lenz C.A., Li J.H., Li Y.-P., Lin X., Liu S.X., Liu Z.A.,
RA   Luros J.S., Maiti R., Marziali A., Militscher J., Miranda M., Nguyen M.,
RA   Nierman W.C., Osborne B.I., Pai G., Peterson J., Pham P.K., Rizzo M.,
RA   Rooney T., Rowley D., Sakano H., Salzberg S.L., Schwartz J.R., Shinn P.,
RA   Southwick A.M., Sun H., Tallon L.J., Tambunga G., Toriumi M.J., Town C.D.,
RA   Utterback T., Van Aken S., Vaysberg M., Vysotskaia V.S., Walker M., Wu D.,
RA   Yu G., Fraser C.M., Venter J.C., Davis R.W.;
RT   "Sequence and analysis of chromosome 1 of the plant Arabidopsis thaliana.";
RL   Nature 408:816-820(2000).
RN   [2]
RP   GENOME REANNOTATION.
RC   STRAIN=cv. Columbia;
RX   PubMed=27862469; DOI=10.1111/tpj.13415;
RA   Cheng C.Y., Krishnakumar V., Chan A.P., Thibaud-Nissen F., Schobel S.,
RA   Town C.D.;
RT   "Araport11: a complete reannotation of the Arabidopsis thaliana reference
RT   genome.";
RL   Plant J. 89:789-804(2017).
RN   [3]
RP   GENOME REANNOTATION.
RC   STRAIN=cv. Columbia;
RG   The Arabidopsis Information Resource (TAIR);
RT   "Community-consensus reference genome of Arabidopsis thaliana Col-0.";
RL   Submitted (FEB-2026) to the EMBL/GenBank/DDBJ databases.
RN   [4]
RP   NUCLEOTIDE SEQUENCE [LARGE SCALE MRNA].
RA   Brover V.V., Troukhan M.E., Alexandrov N.A., Lu Y.-P., Flavell R.B.,
RA   Feldmann K.A.;
RT   "Full-length cDNA from Arabidopsis thaliana.";
RL   Submitted (MAR-2002) to the EMBL/GenBank/DDBJ databases.
RN   [5]
RP   TISSUE SPECIFICITY.
RX   PubMed=11673616; DOI=10.1093/pcp/pce154;
RA   Yokoyama R., Nishitani K.;
RT   "A comprehensive expression analysis of all members of a gene family
RT   encoding cell-wall enzymes allowed us to predict cis-regulatory regions
RT   involved in cell-wall construction in specific organs of Arabidopsis.";
RL   Plant Cell Physiol. 42:1025-1033(2001).
RN   [6]
RP   NOMENCLATURE.
RX   PubMed=12514239; DOI=10.1093/pcp/pcf171;
RA   Rose J.K.C., Braam J., Fry S.C., Nishitani K.;
RT   "The XTH family of enzymes involved in xyloglucan endotransglucosylation
RT   and endohydrolysis: current perspectives and a new unifying nomenclature.";
RL   Plant Cell Physiol. 43:1421-1435(2002).
RN   [7]
RP   TISSUE SPECIFICITY, AND REGULATION BY ATX1 AND ATX2.
RC   STRAIN=cv. Columbia;
RX   PubMed=18375658; DOI=10.1105/tpc.107.056614;
RA   Saleh A., Alvarez-Venegas R., Yilmaz M., Le O., Hou G., Sadder M.,
RA   Al-Abdallat A., Xia Y., Lu G., Ladunga I., Avramova Z.;
RT   "The highly similar Arabidopsis homologs of trithorax ATX1 and ATX2 encode
RT   proteins with divergent biochemical functions.";
RL   Plant Cell 20:568-579(2008).
RN   [8]
RP   TISSUE SPECIFICITY, DEVELOPMENTAL STAGE, SUBCELLULAR LOCATION, AND
RP   MUTAGENESIS OF 90-LEU--ALA-109.
RC   STRAIN=cv. Columbia;
RX   PubMed=19154201; DOI=10.1111/j.1365-313x.2009.03798.x;
RA   Ndamukong I., Chetram A., Saleh A., Avramova Z.;
RT   "Wall-modifying genes regulated by the Arabidopsis homolog of trithorax,
RT   ATX1: repression of the XTH33 gene as a test case.";
RL   Plant J. 58:541-553(2009).
CC   -!- FUNCTION: Catalyzes xyloglucan endohydrolysis (XEH) and/or
CC       endotransglycosylation (XET). Cleaves and religates xyloglucan
CC       polymers, an essential constituent of the primary cell wall, and
CC       thereby participates in cell wall construction of growing tissues (By
CC       similarity). {ECO:0000250|UniProtKB:Q38857}.
CC   -!- CATALYTIC ACTIVITY:
CC       Reaction=breaks a beta-(1->4) bond in the backbone of a xyloglucan and
CC         transfers the xyloglucanyl segment on to O-4 of the non-reducing
CC         terminal glucose residue of an acceptor, which can be a xyloglucan or
CC         an oligosaccharide of xyloglucan.; EC=2.4.1.207;
CC         Evidence={ECO:0000250|UniProtKB:Q38857};
CC   -!- SUBCELLULAR LOCATION: Secreted, cell wall {ECO:0000305}. Secreted,
CC       extracellular space, apoplast {ECO:0000305}. Cell membrane
CC       {ECO:0000269|PubMed:19154201}; Single-pass membrane protein
CC       {ECO:0000269|PubMed:19154201}.
CC   -!- TISSUE SPECIFICITY: Expressed at low levels in vegetative tissues
CC       (roots, stems and seedlings) (PubMed:19154201). Predominantly expressed
CC       in green siliques (PubMed:11673616). Expressed in flowers
CC       (PubMed:18375658). {ECO:0000269|PubMed:11673616,
CC       ECO:0000269|PubMed:18375658, ECO:0000269|PubMed:19154201}.
CC   -!- DEVELOPMENTAL STAGE: Transiently expressed in flowers.
CC       {ECO:0000269|PubMed:19154201}.
CC   -!- INDUCTION: Regulated by ATX1 and ATX2 by epigenetic histone H3
CC       methylation. {ECO:0000269|PubMed:18375658}.
CC   -!- PTM: Contains at least one intrachain disulfide bond essential for its
CC       enzymatic activity. {ECO:0000250}.
CC   -!- MISCELLANEOUS: In contrast to group 1 and group 2
CC       endotransglucosylase/hydrolase proteins, it may not contain the ligase
CC       activity, and may catalyze endohydrolysis xyloglucan polymers only.
CC   -!- SIMILARITY: Belongs to the glycosyl hydrolase 16 family. XTH group 3
CC       subfamily. {ECO:0000305}.
CC   -!- SEQUENCE CAUTION:
CC       Sequence=AAM63851.1; Type=Erroneous initiation; Note=Truncated N-terminus.; Evidence={ECO:0000305};
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DR   EMBL; AC007067; AAD39577.1; -; Genomic_DNA.
DR   EMBL; CP002684; AEE28593.1; -; Genomic_DNA.
DR   EMBL; OZ408683; CAO7026844.1; -; Genomic_DNA.
DR   EMBL; AY086802; AAM63851.1; ALT_INIT; mRNA.
DR   PIR; A86239; A86239.
DR   RefSeq; NP_172525.1; NM_100930.4.
DR   AlphaFoldDB; Q8LC45; -.
DR   SMR; Q8LC45; -.
DR   STRING; 3702.Q8LC45; -.
DR   GlyCosmos; Q8LC45; 4 sites, No reported glycans.
DR   GlyGen; Q8LC45; 4 sites.
DR   iPTMnet; Q8LC45; -.
DR   PaxDb; 3702-Q8LC45; -.
DR   ProteomicsDB; 242491; -.
DR   GeneID; 837596; -.
DR   KEGG; ath:AT1G10550; -.
DR   Araport; AT1G10550; -.
DR   TAIR; AT1G10550; XTH33.
DR   eggNOG; ENOG502QQMG; Eukaryota.
DR   HOGENOM; CLU_048041_1_1_1; -.
DR   InParanoid; Q8LC45; -.
DR   OMA; ACSKVNP; -.
DR   PhylomeDB; Q8LC45; -.
DR   BioCyc; ARA:AT1G10550-MONOMER; -.
DR   BRENDA; 2.4.1.207; 399.
DR   BRENDA; 3.2.1.151; 399.
DR   PRO; PR:Q8LC45; -.
DR   Proteomes; UP000006548; Chromosome 1.
DR   Proteomes; UP001984100; Chromosome 1.
DR   GO; GO:0048046; C:apoplast; IEA:UniProtKB-SubCell.
DR   GO; GO:0005576; C:extracellular region; ISM:TAIR.
DR   GO; GO:0005886; C:plasma membrane; IDA:TAIR.
DR   GO; GO:0004553; F:hydrolase activity, hydrolyzing O-glycosyl compounds; IEA:InterPro.
DR   GO; GO:0030247; F:polysaccharide binding; ISS:UniProtKB.
DR   GO; GO:0016762; F:xyloglucan:xyloglucosyl transferase activity; ISS:UniProtKB.
DR   GO; GO:0042546; P:cell wall biogenesis; IEA:InterPro.
DR   GO; GO:0009831; P:plant-type cell wall modification involved in multidimensional cell growth; IMP:TAIR.
DR   GO; GO:0010411; P:xyloglucan metabolic process; IEA:InterPro.
DR   CDD; cd02176; GH16_XET; 1.
DR   Gene3D; 2.60.120.200; -; 1.
DR   InterPro; IPR000757; Beta-glucanase-like.
DR   InterPro; IPR044791; Beta-glucanase/XTH.
DR   InterPro; IPR013320; ConA-like_dom_sf.
DR   InterPro; IPR010713; XET_C.
DR   InterPro; IPR016455; XTH.
DR   PANTHER; PTHR31062; XYLOGLUCAN ENDOTRANSGLUCOSYLASE/HYDROLASE PROTEIN 8-RELATED; 1.
DR   Pfam; PF00722; Glyco_hydro_16; 1.
DR   Pfam; PF06955; XET_C; 1.
DR   PIRSF; PIRSF005604; XET; 1.
DR   SUPFAM; SSF49899; Concanavalin A-like lectins/glucanases; 1.
DR   PROSITE; PS51762; GH16_2; 1.
PE   1: Evidence at protein level;
KW   Apoplast; Cell membrane; Cell wall; Cell wall biogenesis/degradation;
KW   Disulfide bond; Glycoprotein; Glycosidase; Hydrolase; Membrane;
KW   Reference proteome; Secreted; Signal; Transferase; Transmembrane;
KW   Transmembrane helix.
FT   SIGNAL          1..21
FT                   /evidence="ECO:0000255"
FT   CHAIN           22..310
FT                   /note="Probable xyloglucan endotransglucosylase/hydrolase
FT                   protein 33"
FT                   /id="PRO_0000011833"
FT   TRANSMEM        90..106
FT                   /note="Helical"
FT                   /evidence="ECO:0000255"
FT   DOMAIN          22..233
FT                   /note="GH16"
FT                   /evidence="ECO:0000255|PROSITE-ProRule:PRU01098"
FT   ACT_SITE        118
FT                   /note="Nucleophile"
FT                   /evidence="ECO:0000255|PROSITE-ProRule:PRU10064"
FT   ACT_SITE        122
FT                   /note="Proton donor"
FT                   /evidence="ECO:0000255|PROSITE-ProRule:PRU10064"
FT   BINDING         122
FT                   /ligand="xyloglucan"
FT                   /ligand_id="ChEBI:CHEBI:18233"
FT                   /evidence="ECO:0000250|UniProtKB:Q8GZD5"
FT   BINDING         135..137
FT                   /ligand="xyloglucan"
FT                   /ligand_id="ChEBI:CHEBI:18233"
FT                   /evidence="ECO:0000250|UniProtKB:Q8GZD5"
FT   BINDING         145..149
FT                   /ligand="xyloglucan"
FT                   /ligand_id="ChEBI:CHEBI:18233"
FT                   /evidence="ECO:0000250|UniProtKB:Q8GZD5"
FT   BINDING         212..213
FT                   /ligand="xyloglucan"
FT                   /ligand_id="ChEBI:CHEBI:18233"
FT                   /evidence="ECO:0000250|UniProtKB:Q8GZD5"
FT   BINDING         217
FT                   /ligand="xyloglucan"
FT                   /ligand_id="ChEBI:CHEBI:18233"
FT                   /evidence="ECO:0000250|UniProtKB:Q8GZD5"
FT   BINDING         301
FT                   /ligand="xyloglucan"
FT                   /ligand_id="ChEBI:CHEBI:18233"
FT                   /evidence="ECO:0000250|UniProtKB:Q8GZD5"
FT   SITE            120
FT                   /note="Important for catalytic activity"
FT                   /evidence="ECO:0000250|UniProtKB:Q8GZD5"
FT   CARBOHYD        30
FT                   /note="N-linked (GlcNAc...) asparagine"
FT                   /evidence="ECO:0000255|PROSITE-ProRule:PRU00498"
FT   CARBOHYD        59
FT                   /note="N-linked (GlcNAc...) asparagine"
FT                   /evidence="ECO:0000255|PROSITE-ProRule:PRU00498"
FT   CARBOHYD        141
FT                   /note="N-linked (GlcNAc...) asparagine"
FT                   /evidence="ECO:0000255|PROSITE-ProRule:PRU00498"
FT   CARBOHYD        245
FT                   /note="N-linked (GlcNAc...) asparagine"
FT                   /evidence="ECO:0000255|PROSITE-ProRule:PRU00498"
FT   DISULFID        296..309
FT                   /evidence="ECO:0000250|UniProtKB:Q8GZD5"
FT   MUTAGEN         90..109
FT                   /note="Missing: Abnormal subcellular cytoplasmic
FT                   localization organized as discrete aggregated bodies."
FT                   /evidence="ECO:0000269|PubMed:19154201"
FT   CONFLICT        21
FT                   /note="S -> A (in Ref. 4; AAM63851)"
FT                   /evidence="ECO:0000305"
FT   CONFLICT        80
FT                   /note="K -> N (in Ref. 4; AAM63851)"
FT                   /evidence="ECO:0000305"
SQ   SEQUENCE   310 AA;  34644 MW;  F3228D8CB96EF89D CRC64;
     MKIMWETAVV FCLCSLSLVS SHSRKFTTPN VTRLTDQFSK IAIENGFSRR FGAHNIQVNG
     SLAKLTLDKS SGAGLVSKNK YHYGFFSARL KLPAGFASGV VVAFYLSNAE TYPKSHDEID
     IELLGRSRRD DWTIQTNVYA NGSTRTGREE KFYFWFDPTQ AFHDYTLIWN SHHTVFLVDN
     IPVRQFPNRG AFTSAYPSKP MSLYVTVWDG SEWATKGGKY PVNYKYAPFV VSVADVELSG
     CSVNNGSSTG SGPCTKSGGS ISSLDPVDGQ DFATLSKNQI NAMDWARRKL MFYSYCSDKP
     RYKVMPAECN
//