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861  structures 16337  species 15  interactions 45381  sequences 147  architectures

Clan: Calycin (CL0116)


Calycin superfamily Add an annotation

The calycin structural superfamily [1-3] includes the lipocalins, the fatty acid-binding proteins (FABPs).

This clan contains 20 families and the total number of domains in the clan is 45381. The clan was built by A Bateman.

Literature references

  1. Flower DR, North AC, Sansom CE; , Biochim Biophys Acta 2000;1482:9-24.: The lipocalin protein family: structural and sequence overview. PUBMED:11058743 EPMC:11058743
  2. Flower DR; , FEBS Lett 1993;333:99-102.: Structural relationship of streptavidin to the calycin protein superfamily. PUBMED:8224179 EPMC:8224179
  3. Flower DR, North AC, Attwood TK; , Protein Sci 1993;2:753-761.: Structure and sequence relationships in the lipocalins and related proteins. PUBMED:7684291 EPMC:7684291


This clan contains the following 20 member families:

ApoM CrtC DUF3642 DUF4488 DUF4822 His_binding Lipocalin Lipocalin_2 Lipocalin_3 Lipocalin_4 Lipocalin_5 Lipocalin_7 Lipocalin_8 META Nitrophorin NlpE Svf1 Triabin VDE ZinT

External database links

Domain organisation

Below is a listing of the unique domain organisations or architectures from this clan. More...

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The table below shows the number of occurrences of each domain throughout the sequence database. More...

Pfam family Num. domains Alignment
META (PF03724) 9438 (20.8%) View
ZinT (PF09223) 9213 (20.3%) View
Lipocalin_2 (PF08212) 7634 (16.8%) View
NlpE (PF04170) 5256 (11.6%) View
Lipocalin (PF00061) 3152 (6.9%) View
CrtC (PF07143) 2962 (6.5%) View
DUF4822 (PF16103) 2539 (5.6%) View
His_binding (PF02098) 1235 (2.7%) View
Lipocalin_5 (PF13924) 655 (1.4%) View
Lipocalin_4 (PF13648) 617 (1.4%) View
DUF3642 (PF12182) 487 (1.1%) View
Triabin (PF03973) 481 (1.1%) View
Svf1 (PF08622) 348 (0.8%) View
Lipocalin_7 (PF14651) 293 (0.6%) View
Lipocalin_8 (PF16585) 287 (0.6%) View
Lipocalin_3 (PF12702) 257 (0.6%) View
DUF4488 (PF14869) 219 (0.5%) View
VDE (PF07137) 158 (0.3%) View
ApoM (PF11032) 91 (0.2%) View
Nitrophorin (PF02087) 59 (0.1%) View
Total: 20 Total: 45381 Clan alignment

Please note: Clan alignments can be very large and can cause problems for some browsers. Read the note above before viewing.

Family relationships

This diagram shows the relationships between members of this clan. More...

Species distribution

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This tree shows the occurrence of the domains in this clan across different species. More...



There are 15 interactions for this clan. More...

Interacting families
ApoM ApoM
CrtC CrtC
His_binding His_binding
Lipocalin fn3
Lipocalin_2 Lipocalin_2
Lipocalin_3 Lipocalin_3
Lipocalin_7 Lipocalin_7
MACPF Lipocalin
Nitrophorin Nitrophorin
NlpE NlpE
Transthyretin Lipocalin
Triabin Triabin
Trypsin Triabin


For those sequences which have a structure in the Protein DataBank, we use the mapping between UniProt, PDB and Pfam coordinate systems from the MSD group, to allow us to map Pfam domains onto UniProt three-dimensional structures. The table below shows the mapping between the Pfam families in this clan, the corresponding UniProt entries, and the region of the three-dimensional structures that are available for that sequence.

Loading structure mapping...