DUFMech

Domain and protein families of unknown function, including historical DUFs.

8,296Families

8,238Families with InterPro IDs

1,906Families with structures

8,242Families with AlphaFold models

17,971,301Per-family protein total

19,768,727Per-family match total

DUF examples curated in other Mechs

Family mentions and protein associations are contextual links, not functional validation.

Family	Mech	Record	Protein	Link basis
UPF0014 not in worklist	TaxonMech	Lactobacillus delbrueckii		record mentions unlisted short name
UPF0014 not in worklist	TaxonMech	Lactobacillus delbrueckii subsp. lactis		record mentions unlisted short name
UPF0014 not in worklist	TaxonMech	Lactobacillus leichmannii		record mentions unlisted short name
UPF0018 not in worklist	TaxonMech	Lactobacillus delbrueckii		record mentions unlisted short name
UPF0018 not in worklist	TaxonMech	Lactobacillus delbrueckii subsp. lactis		record mentions unlisted short name
UPF0018 not in worklist	TaxonMech	Lactobacillus leichmannii		record mentions unlisted short name
UPF0037 not in worklist	TaxonMech	Lactobacillus delbrueckii		record mentions unlisted short name
UPF0037 not in worklist	TaxonMech	Lactobacillus delbrueckii subsp. lactis		record mentions unlisted short name
UPF0037 not in worklist	TaxonMech	Lactobacillus leichmannii		record mentions unlisted short name
UPF0265 not in worklist	CellStructureMech	H-body		record mentions unlisted short name
UPF0265 not in worklist	CellStructureMech	TmaR condensate		record mentions unlisted short name
GmrSD_N (PF03235)	TaxonMech	Sinorhizobium xinjiangense		record mentions previous pfam name
GmrSD_N (PF03235)	TraitMech	DUF262 Schlafen system		record mentions previous pfam name
DUF348 (PF03990)	TraitMech	dormancy	P9WG29 Resuscitation-promoting factor RpfB	uniprot pfam xref
DUF496 (PF04363)	CellStructureMech	H-body		record mentions interpro id, record mentions short name
DUF496 (PF04363)	CellStructureMech	H-body	P0A8M6 Pole-localizer protein TmaR	uniprot pfam xref
DUF496 (PF04363)	CellStructureMech	TmaR condensate		record mentions short name
DUF496 (PF04363)	CellStructureMech	TmaR condensate	P0A8M6 Pole-localizer protein TmaR	uniprot pfam xref
DUF543 (PF04418)	CellStructureMech	MIC10 subcomplex		record mentions interpro id
DUF1674 (PF07896)	AntibioticMech	fluconazole	A0A1D8PGP5 Succinate dehydrogenase assembly factor 4, mitochondrial	uniprot pfam xref

All frozen cross-Mech examples

Per-family totals are sums of reported InterPro counters, not unique proteins or matches. 0 families lack protein counts; 0 lack match counts.

Browse by seed category

Residue-level domain matches

PF04149: Domain of unknown function (DUF397) (2 supplied protein members)

Families

Download the complete family index (JSON)

8,296 of 8,296 families. Page 1 of 166.

Pfam	Family	Seed status	Characterization	Evidence counts	Proteins	Structures	AlphaFold	Other Mechs	Curation status
PF13193	AMP-binding enzyme C-terminal domain AMP-binding_C	EX DUF	UNSCORED	Not scored	284,163	297	168,232	not covered by the cross-Mech scan	SEEDED
PF00672	HAMP domain HAMP	EX DUF	UNSCORED	Not scored	257,581	46	151,473	not covered by the cross-Mech scan	SEEDED
PF00990	Diguanylate cyclase, GGDEF domain GGDEF	EX DUF	UNSCORED	Not scored	238,353	70	144,091	not covered by the cross-Mech scan	SEEDED
PF01535	PPR repeat PPR	EX DUF	UNSCORED	Not scored	228,033	30	180,864	not covered by the cross-Mech scan	SEEDED
PF00892	EamA-like transporter family EamA	EX DUF	UNSCORED	Not scored	219,191	3	143,070	not covered by the cross-Mech scan	SEEDED
PF02687	FtsX-like permease C-terminal FtsX	EX DUF	UNSCORED	Not scored	143,181	72	90,109	not covered by the cross-Mech scan	SEEDED
PF00563	EAL domain EAL	EX DUF	UNSCORED	Not scored	131,837	75	78,574	not covered by the cross-Mech scan	SEEDED
PF13715	CarboxypepD_reg-like domain CarbopepD_reg_2	EX DUF	UNSCORED	Not scored	114,619	19	74,447	not covered by the cross-Mech scan	SEEDED
PF01554	MatE MatE	EX DUF	UNSCORED	Not scored	99,069	43	70,770	not covered by the cross-Mech scan	SEEDED
PF01757	Acyltransferase domain Acyl_transf_3	EX DUF	UNSCORED	Not scored	79,491	0	51,499	not covered by the cross-Mech scan	SEEDED
PF01925	Sulfite exporter TauE/SafE TauE	EX DUF	UNSCORED	Not scored	74,133	0	48,156	not covered by the cross-Mech scan	SEEDED
PF01042	Endoribonuclease L-PSP Ribonuc_L-PSP	EX DUF	UNSCORED	Not scored	74,014	76	48,953	not covered by the cross-Mech scan	SEEDED
PF00924	Mechanosensitive ion channel, beta-domain MS_channel_2nd	EX DUF	UNSCORED	Not scored	69,957	65	46,372	not covered by the cross-Mech scan	SEEDED
PF01638	HxlR-like helix-turn-helix HxlR	EX DUF	UNSCORED	Not scored	69,591	18	41,510	not covered by the cross-Mech scan	SEEDED
PF00668	Condensation domain Condensation	EX DUF	UNSCORED	Not scored	68,562	107	14,105	not covered by the cross-Mech scan	SEEDED
PF03401	Tripartite tricarboxylate transporter family receptor TctC	EX DUF	UNSCORED	Not scored	64,590	13	38,963	not covered by the cross-Mech scan	SEEDED
PF01168	Alanine racemase, N-terminal domain Ala_racemase_N	EX DUF	UNSCORED	Not scored	61,405	114	39,913	not covered by the cross-Mech scan	SEEDED
PF11951	Fungal specific transcription factor domain Fungal_trans_2	EX DUF	UNSCORED	Not scored	61,055	4	51,044	not covered by the cross-Mech scan	SEEDED
PF01594	AI-2E family transporter AI-2E_transport	EX DUF	UNSCORED	Not scored	58,169	2	37,191	not covered by the cross-Mech scan	SEEDED
PF01595	Cyclin M transmembrane N-terminal domain CNNM	EX DUF	UNSCORED	Not scored	56,844	4	38,019	not covered by the cross-Mech scan	SEEDED
PF07717	Oligonucleotide/oligosaccharide-binding (OB)-fold OB_NTP_bind	EX DUF	UNSCORED	Not scored	55,636	160	34,331	not covered by the cross-Mech scan	SEEDED
PF06429	Flagellar basal body rod FlgEFG protein C-terminal Flg_bbr_C	EX DUF	UNSCORED	Not scored	48,344	48	31,623	not covered by the cross-Mech scan	SEEDED
PF01207	Dihydrouridine synthase (Dus) Dus	EX DUF	UNSCORED	Not scored	46,157	15	33,123	not covered by the cross-Mech scan	SEEDED
PF01026	TatD related DNase TatD_DNase	EX DUF	UNSCORED	Not scored	42,146	16	29,396	not covered by the cross-Mech scan	SEEDED
PF03151	Triose-phosphate Transporter family TPT	EX DUF	UNSCORED	Not scored	41,491	2	34,453	not covered by the cross-Mech scan	SEEDED
PF02082	Iron-dependent Transcriptional regulator Rrf2	EX DUF	UNSCORED	Not scored	39,881	21	25,715	not covered by the cross-Mech scan	SEEDED
PF02585	GlcNAc-PI de-N-acetylase PIG-L	EX DUF	UNSCORED	Not scored	39,336	28	24,676	not covered by the cross-Mech scan	SEEDED
PF03781	Sulfatase-modifying factor enzyme 1-like domain FGE-sulfatase	EX DUF	UNSCORED	Not scored	38,188	65	25,146	not covered by the cross-Mech scan	SEEDED
PF04828	Glutathione-dependent formaldehyde-activating enzyme GFA	EX DUF	UNSCORED	Not scored	38,163	4	26,902	not covered by the cross-Mech scan	SEEDED
PF04149	Domain of unknown function (DUF397) DUF397	UNKNOWN CANDIDATE	UNSCORED	Not scored	37,657	0	19,000	ProteinTraitsMech trait record	SEEDED
PF19054	Domain of unknown function (DUF5753) DUF5753	UNKNOWN CANDIDATE	UNSCORED	Not scored	37,511	0	19,007	ProteinTraitsMech trait record	SEEDED
PF02754	Cysteine-rich domain CCG	EX DUF	UNSCORED	Not scored	37,412	19	23,792	not covered by the cross-Mech scan	SEEDED
PF01883	Iron-sulfur cluster assembly protein FeS_assembly_P	EX DUF	UNSCORED	Not scored	37,284	15	24,936	not covered by the cross-Mech scan	SEEDED
PF02597	ThiS family ThiS	EX DUF	UNSCORED	Not scored	36,990	39	24,446	not covered by the cross-Mech scan	SEEDED
PF02678	Pirin Pirin	EX DUF	UNSCORED	Not scored	36,769	22	23,663	not covered by the cross-Mech scan	SEEDED
PF03006	Haemolysin-III related HlyIII	EX DUF	UNSCORED	Not scored	35,375	11	27,402	not covered by the cross-Mech scan	SEEDED
PF05685	Putative restriction endonuclease Uma2	EX DUF	UNSCORED	Not scored	35,097	4	20,569	not covered by the cross-Mech scan	SEEDED
PF01938	TRAM domain TRAM	EX DUF	UNSCORED	Not scored	35,071	18	24,317	not covered by the cross-Mech scan	SEEDED
PF03357	Snf7 Snf7	EX DUF	UNSCORED	Not scored	34,943	31	29,923	not covered by the cross-Mech scan	SEEDED
PF02629	CoA binding domain CoA_binding	EX DUF	UNSCORED	Not scored	34,081	92	24,075	not covered by the cross-Mech scan	SEEDED
PF01171	PP-loop domain ATP_bind_3	EX DUF	UNSCORED	Not scored	33,613	16	23,049	not covered by the cross-Mech scan	SEEDED
PF01661	Macro domain Macro	EX DUF	UNSCORED	Not scored	32,372	1,152	21,017	not covered by the cross-Mech scan	SEEDED
PF11838	ERAP1-like C-terminal domain ERAP1_C	EX DUF	UNSCORED	Not scored	32,309	103	24,586	not covered by the cross-Mech scan	SEEDED
PF01255	Putative undecaprenyl diphosphate synthase Prenyltransf	EX DUF	UNSCORED	Not scored	31,979	103	22,269	not covered by the cross-Mech scan	SEEDED
PF01513	ATP-NAD kinase N-terminal domain NAD_kinase	EX DUF	UNSCORED	Not scored	31,526	119	23,017	not covered by the cross-Mech scan	SEEDED
PF01882	Protein of unknown function DUF58 DUF58	UNKNOWN CANDIDATE	UNSCORED	Not scored	31,251	0	19,995	ProteinTraitsMech: 2; ProteinTraitsMech trait record	SEEDED
PF01641	SelR domain SelR	EX DUF	UNSCORED	Not scored	30,911	22	21,713	not covered by the cross-Mech scan	SEEDED
PF05977	Transmembrane secretion effector MFS_3	EX DUF	UNSCORED	Not scored	30,466	0	17,747	not covered by the cross-Mech scan	SEEDED
PF01458	SUF system FeS cluster assembly, SufBD core domain SUFBD_core	EX DUF	UNSCORED	Not scored	30,443	8	20,235	not covered by the cross-Mech scan	SEEDED
PF25372	F-box/LRR-repeat protein 15, leucine rich repeat domain LRR_FBXL15	EX DUF	UNSCORED	Not scored	30,220	9	24,573	not covered by the cross-Mech scan	SEEDED

Protein family sizes
Families by reported InterPro protein count

1-991,734

100-9993,495

1,000-9,9992,720

10,000+341

Not available0

Each family contributes once. Proteins can belong to multiple families.

Status and evidence

Seed status: A name-based classification of frozen InterPro/Pfam metadata. UNKNOWN CANDIDATE means the metadata explicitly says the function is unknown. KNOWN HISTORICAL DUF means a DUF name matched without that wording; this heuristic is not proof of a known function and does not establish experimental characterization. EX DUF means Pfam renamed the family away from a DUF/UPF name, as recorded in Pfam's previous identifiers; a rename usually follows published work on some members but is naming history, not proof of function for every member. Some EX DUF families' current names or descriptions still say the function is unknown; their classification basis lists this, and scoring does not treat them as characterized. FALSE POSITIVE TEXT HIT means the naming rules did not match.
Characterization: A separate evidence-scoring result. UNSCORED means no score has been calculated; it is not evidence that the family lacks a known function. Missing scores are not negative evidence. PARTIALLY CHARACTERIZED has partial support; KNOWN HISTORICAL DUF can inherit the seed label or reflect a known-function signal. Neither label implies experimental validation.
Evidence counts: Source-specific signals, not unique proteins, publications, or confidence scores. Known counts Rhea reactions and experimentally supported GO molecular-function annotations. Partial counts functional/domain assignments. Context counts structural, environmental, orthology, interaction and neighborhood signals; context alone does not assign function. Repeated annotations may not be independent.
Curation status: Reported separately from seed classification and characterization. SNAPSHOT ONLY means no curated metadata was supplied for this build. SEEDED denotes a source-derived record, not an expert-reviewed functional claim.
Missing counts: Not available means the source did not supply that counter. A zero is a reported count. Not scored means evidence counts are unavailable.