id: L7N6F8 gene_symbol: Derp23 product_type: PROTEIN status: DRAFT taxon: id: NCBITaxon:6956 label: Dermatophagoides pteronyssinus description: >- Der p 23, a major house dust mite allergen associated with the peritrophic matrix of mite faecal pellets. It contains a peritrophin-A-type (ChtBD2) chitin-binding domain fold, but direct assays found no chitin binding in vitro, so its molecular function is unresolved. Despite its small size and minor abundance it is a major allergen, recognized by IgE in a large fraction of dust-mite-allergic patients. alternative_records: - id: A0ABQ8JBE4 relationship: REFERENCE_PROTEOME_CANDIDATE reference_proteome: UP000887458 reviewed_on: '2026-10-19' reason: Retain L7N6F8 as the primary Swiss-Prot accession. The leading small chitin-binding protein is a plausible Der p 23 counterpart, but global identity is 75.51% with substitutions and indels. Other chitin-binding proteins are present, and no shared source/target locus cross-reference establishes identity. Retain a candidate pending genomic mapping and gene-model assessment. evidence: - type: PROTEOME_SEARCH description: MMseqs2 searched 14,675 sequences across UP000887458 at E <= 1e-5 and sensitivity 7.5, returning 4 hits. Every returned sequence was globally aligned using BLOSUM62 with gap-open -10 and extension -0.5. Scores and sequences for all 4 returned candidates are retained, with 4 detailed alignment files. The heuristic search does not establish genomic absence or unique locus identity. supported_by: - reference_id: file:DERPT/Derp23/Derp23-record-evidence.yaml supporting_text: 'target_sequence_count: 14675' - reference_id: file:DERPT/Derp23/Derp23-record-evidence.yaml supporting_text: 'candidate_count: 4' - type: SEQUENCE_COMPARISON description: 'A0ABQ8JBE4: 74 identities across 98 global-alignment columns (75.5102% identity including gaps), 9 substitutions and 15 gap columns. Query coverage is 92.2222%; target coverage is 91.2088%. Sequence similarity is interpreted in the manual rationale. Identity over paired residues is 89.1566% (74/83); gap columns are excluded from this denominator.' supported_by: - reference_id: file:DERPT/Derp23/Derp23-record-evidence.yaml supporting_text: |- query_length: 90 target_length: 91 alignment_columns: 98 identities: 74 mismatches: 9 gap_columns: 15 identity_percent: 75.5102 query_coverage_percent: 92.2222 target_coverage_percent: 91.2088 - type: PROTEOME_MEMBERSHIP description: The primary accession is outside every searched exact-taxon reference proteome. Current UniProt records place A0ABQ8JBE4 in UP000887458 and give it the same taxon as the primary. supported_by: - reference_id: file:DERPT/Derp23/Derp23-record-evidence.yaml supporting_text: 'primary_in_any_reference_proteome: false' - reference_id: file:DERPT/Derp23/Derp23-record-evidence.yaml supporting_text: 'alternative_in_reference_proteome: true' - reference_id: file:DERPT/Derp23/Derp23-record-evidence.yaml supporting_text: 'same_taxon: true' - type: RECORD_HISTORY description: 'Sampled UniSave observations: 09-DEC-2015, entry version 10.: no Proteomes cross-reference; 17-JUN-2020, entry version 26.: no Proteomes cross-reference; 24-JUL-2024, entry version 33.: UP000515146. These dated observations do not establish uninterrupted membership/absence, the exact change date, or UniProt''s motivation.' supported_by: - reference_id: file:DERPT/Derp23/Derp23-record-evidence.yaml supporting_text: |- entry_date: 09-DEC-2015, entry version 10. proteomes: [] - reference_id: file:DERPT/Derp23/Derp23-record-evidence.yaml supporting_text: |- entry_date: 17-JUN-2020, entry version 26. proteomes: [] - reference_id: file:DERPT/Derp23/Derp23-record-evidence.yaml supporting_text: |- entry_date: 24-JUL-2024, entry version 33. proteomes: - UP000515146 existing_annotations: - term: id: GO:0005576 label: extracellular region evidence_type: IEA original_reference_id: GO_REF:0000120 qualifier: located_in review: summary: Der p 23 is secreted/excreted with mite faecal pellets (peritrophic matrix); extracellular localization is correct. action: ACCEPT reason: Excreted allergen of the faecal-pellet peritrophic matrix. - term: id: GO:0005783 label: endoplasmic reticulum evidence_type: IEA original_reference_id: GO_REF:0000044 qualifier: located_in review: summary: ER localization reflects the secretory route in mite gut cells. action: KEEP_AS_NON_CORE reason: Biosynthetic/secretory-route compartment; not the functional site. - term: id: GO:0031410 label: cytoplasmic vesicle evidence_type: IEA original_reference_id: GO_REF:0000044 qualifier: located_in review: summary: Vesicular localization reflects the secretory route. action: KEEP_AS_NON_CORE reason: Secretory-route compartment; not the functional site. - term: id: GO:0005576 label: extracellular region evidence_type: IDA original_reference_id: PMID:23460742 qualifier: located_in review: summary: Der p 23 was experimentally localized to the peritrophic matrix of mite faecal pellets (excreted). action: ACCEPT reason: Experimental support for extracellular/excreted localization. supported_by: - reference_id: PMID:23460742 supporting_text: peritrophic matrix of mite fecal pellets - term: id: GO:0008061 label: chitin binding evidence_type: IDA original_reference_id: PMID:26602749 qualifier: enables negated: true review: summary: >- This is a NOT (negated) annotation: GOA records that Der p 23 does NOT bind chitin. Despite its peritrophin-A (ChtBD2) chitin-binding-domain fold, direct assays (PMID:26602749) found no chitin binding in vitro, as also stated in UniProt. The negation is correct and informative. action: ACCEPT reason: >- The negated annotation accurately captures the experimental finding that Der p 23 lacks chitin-binding activity in vitro; it correctly prevents domain-based over-annotation of chitin binding. supported_by: - reference_id: file:DERPT/Derp23/Derp23-uniprot.txt record_section: ["CC:FUNCTION"] supporting_text: Does not bind chitin in vitro. - term: id: GO:0019863 label: IgE binding evidence_type: IMP original_reference_id: PMID:24733847 qualifier: enables review: summary: Der p 23 binds IgE (basis of its allergenicity and hypoallergen-vaccine design); this reflects allergenicity toward humans, not its endogenous mite function. action: KEEP_AS_NON_CORE reason: Allergen/IgE-reactivity property, not the protein's endogenous molecular function. - term: id: GO:0031410 label: cytoplasmic vesicle evidence_type: IDA original_reference_id: PMID:23460742 qualifier: located_in review: summary: Experimental vesicular localization consistent with the secretory route. action: KEEP_AS_NON_CORE reason: Secretory-route compartment; not the functional site. - term: id: GO:0005783 label: endoplasmic reticulum evidence_type: IDA original_reference_id: PMID:23460742 qualifier: located_in review: summary: Experimental ER localization consistent with the secretory route. action: KEEP_AS_NON_CORE reason: Biosynthetic/secretory-route compartment; not the functional site. core_functions: - description: >- Secreted (faecal-pellet peritrophic-matrix) major mite allergen with a peritrophin-A (ChtBD2) chitin-binding domain fold. Its molecular function is unresolved: despite the domain, direct assays found no chitin binding in vitro. locations: - id: GO:0005576 label: extracellular region knowledge_gaps: - gap_statement: >- The molecular function of Der p 23 is undetermined: it has a peritrophin-A chitin-binding-domain fold but does not bind chitin in vitro, and no alternative ligand or activity has been established. boundary: >- Established: Der p 23 is a secreted peritrophin-like mite protein of the faecal peritrophic matrix. Unknown: its actual ligand/biochemical activity (chitin binding is contradicted by direct assay). gap_kind: - BIOLOGY provenance: - reference_id: file:DERPT/Derp23/Derp23-uniprot.txt supporting_text: Does not bind chitin in vitro. proposed_new_terms: [] suggested_questions: - question: If Der p 23 does not bind chitin, what is the endogenous ligand/function of its peritrophin-A domain in the mite peritrophic matrix? experts: [] suggested_experiments: - hypothesis: Der p 23's peritrophin domain binds a peritrophic-matrix component other than chitin (e.g. a glycoprotein or glycan). description: Screen recombinant Der p 23 for binding to peritrophic-matrix glycans/glycoproteins by pull-down and glycan-array assays. experiment_type: ligand identification / binding assay references: - id: file:DERPT/Derp23/Derp23-record-evidence.yaml title: Compact archived record and sequence evidence for L7N6F8 - id: GO_REF:0000044 title: Gene Ontology annotation based on UniProtKB/Swiss-Prot Subcellular Location vocabulary mapping, accompanied by conservative changes to GO terms applied by UniProt findings: [] - id: GO_REF:0000120 title: Combined Automated Annotation using Multiple IEA Methods findings: [] - id: PMID:23460742 title: Identification of Der p 23, a peritrophin-like protein, as a new major Dermatophagoides pteronyssinus allergen associated with the peritrophic matrix of mite fecal pellets. findings: - statement: Der p 23 is a peritrophin-like mite allergen associated with the peritrophic matrix of faecal pellets. reference_review: relevance: HIGH correctness: VERIFIED review_notes: Primary identification of Der p 23 and its peritrophic-matrix/faecal-pellet localization. - id: PMID:26602749 title: Serological, genomic and structural analyses of the major mite allergen Der p 23. findings: - statement: Structural analysis of Der p 23; the protein does not bind chitin in vitro despite its peritrophin-A domain fold. reference_review: relevance: HIGH correctness: VERIFIED review_notes: Cited for the chitin-binding annotation but reports no chitin binding in vitro; basis for flagging that annotation UNDECIDED. - id: PMID:24733847 title: Conversion of Der p 23, a new major house dust mite allergen, into a hypoallergenic vaccine. findings: - statement: Der p 23 is IgE-reactive; engineered hypoallergenic variants reduce IgE binding for vaccine use. reference_review: relevance: MEDIUM correctness: VERIFIED review_notes: Supports IgE-binding (allergenicity) property of Der p 23. - id: file:DERPT/Derp23/Derp23-uniprot.txt title: UniProt entry L7N6F8 (Major mite allergen Der p 23), Dermatophagoides pteronyssinus findings: - statement: Der p 23 is a secreted peritrophin-like major mite allergen that does not bind chitin in vitro. record_section: ["CC:FUNCTION"] supporting_text: Does not bind chitin in vitro. reference_review: relevance: HIGH correctness: VERIFIED review_notes: Curated UniProt record; source for the "does not bind chitin in vitro" finding underlying the function knowledge gap.