{PDOC51802}
{PS51802; ZF_CCHHC}
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* Zinc finger CCHHC-type profile *
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Zinc finger  (ZF)  proteins are a large family of metalloproteins that utilize
zinc for  structural  purposes.  Zinc coordinates to a combination of cysteine
thiol and  histidine  imidazole  residues  within  the  ZF polypetide sequence
resulting in  a  folded  and  functional protein. The CCHHC family of ZFs is a
small family  of  "nonclassical" ZFs that are essential for the development of
the central  nervous  system.  These  proteins have up to seven putative zinc-
binding sequences,  usually  arranged  in  sets  of two or more sequences. The
CCHHC-type zinc  finger is able to bind specific double-stranded DNA sequences
[1,2,3,4,5].

The CCHHC-type  zinc  finger  contains  five absolutely conserved cysteine and
histidine residues  (rather  than  the  more  usual  four)  with  the sequence
C-P-x-P-G-C-x-G-x-G-H-x(7)-H-R-x(4)-C. The  second histidine has been shown to
coordinate Zn(II) along with the three cysteines residues. The first His plays
a different  role  in  stabilizing  the structure, stacking between the metal-
binding core  and an aromatic residue that is relatively conserved within this
domain family.  CCHHC-type zinc fingers form small compact structures that can
sit entirely within the major groove of DNA (see <PDB:2JX1>) [1,2,3,4,5].

Some proteins known to contain a CCHHC-type zinc finger are listed below:

 - Animal  myelin  transcription  factor  1  (MyT1),  or  neural zinc finger 2
   (NZF2), a transcription factor that contains seven copies of the CCHHC-type
   zinc finger. It binds to sites in the proteolipid protein promoter.
 - Vertebrate  MyT1-like  (MyT1L/NZF1),  appears  to  be  involved  in  neural
   development.
 - Vertebrate  Suppressor  of  Tumorigenicity  18 (ST18/NZF3), a breast cancer
   tumor suppressor.
 - Vertebrate  L3MBTL,  a  member  of  the  Polycomb  group of proteins, which
   function as transcriptional repressors in large protein complexes.
 - Vertebrate L3MBTL3, a possible tumor suppressor.
 - Vertebrate L3MBTL4.

The profile we developed covers the entire CCHHC-type zinc finger.

-Sequences known to belong to this class detected by the profile: ALL.
-Other sequence(s) detected in Swiss-Prot: NONE.
-Last update: June 2016 / First entry.

[ 1] Gamsjaeger R., Swanton M.K., Kobus F.J., Lehtomaki E., Lowry J.A.,
     Kwan A.H., Matthews J.M., Mackay J.P.
     "Structural and biophysical analysis of the DNA binding properties of
     myelin transcription factor 1."
     J. Biol. Chem. 283:5158-5167(2008).
     PubMed=18073212; DOI=10.1074/jbc.M703772200
[ 2] Gamsjaeger R., O'Connell M.R., Cubeddu L., Shepherd N.E., Lowry J.A.,
     Kwan A.H., Vandevenne M., Swanton M.K., Matthews J.M., Mackay J.P.
     "A structural analysis of DNA binding by myelin transcription factor 1
     double zinc fingers."
     J. Biol. Chem. 288:35180-35191(2013).
     PubMed=24097990; DOI=10.1074/jbc.M113.482075
[ 3] Lee S.J., Michel S.L.J.
     "Structural metal sites in nonclassical zinc finger proteins involved
     in transcriptional and translational regulation."
     Acc. Chem. Res. 47:2643-2650(2014).
     PubMed=25098749; DOI=10.1021/ar500182d
[ 4] Besold A.N., Michel S.L.
     "Neural Zinc Finger Factor/Myelin Transcription Factor Proteins: Metal
     Binding, Fold, and Function."
     Biochemistry 54:4443-4452(2015).
     PubMed=26158299; DOI=10.1021/bi501371a
[ 5] Berkovits-Cymet H.J., Amann B.T., Berg J.M.
     "Solution structure of a CCHHC domain of neural zinc finger factor-1
     and its implications for DNA binding."
     Biochemistry 43:898-903(2004).
     PubMed=14744132; DOI=10.1021/bi035159d

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