{PDOC00184}
{PS00209; HEMOCYANIN_1}
{PS00210; HEMOCYANIN_2}
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* Arthropod hemocyanins / insect LSPs signatures *
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Hemocyanins are copper-containing  oxygen  carriers occurring freely dissolved
in the hemolymph of many molluscs  and  arthropods [1].  Arthropod hemocyanins
consist  of  hexamer or  multi-hexamers with  subunits of about 75 Kd. Each of
these subunits binds two copper ions.

Larval storage proteins (LSP) [2] are proteins  from the hemolymph of insects,
which may serve as  a  store of  amino acids  for synthesis of adult proteins.
There are two classes of LSP's: arylphorins,  which are rich in aromatic amino
acids, and methionine-rich LSP's.  LSP's forms hexameric complexes.  LSP's are
structurally related to arthropod hemocyanins.

In the lepidopteran Trichoplusia ni  a  protein  has  been  found [3] which is
associated with larval metamorphosis.  This  protein,  which  is called acidic
juvenile hormone-suppressible protein 1 (AJSP-1) is  also structurally related
to arthropod hemocyanins.

As signature patterns for these  proteins  we selected  two conserved regions,
the first  of  these  regions is located  in the  N-terminal  section of these
proteins  and  include a conserved  histidine  residue  which, in hemocyanins,
binds a copper atom.  The second pattern is located in the central part of the
protein.

-Consensus pattern: Y-[FYW]-x-E-D-[LIVM]-x(2)-N-x(6)-H-x(3)-P
                    [H is a copper ligand in hemocyanins]
-Sequences known to belong to this class detected by the pattern: ALL,  except
 most LSPs.
-Other sequence(s) detected in Swiss-Prot: NONE.

-Consensus pattern: T-x(2)-R-D-P-x-[FY]-[FYW]
-Sequences known to belong to this class detected by the pattern: ALL,  except
 one LSP.
-Other sequence(s) detected in Swiss-Prot: 2.

-Note: See  also  the  pattern  for  the  copper B binding site  of tyrosinase
 <PDOC00398>;  this  pattern  will  also  pick  up  all arthropod and  mollusc
 hemocyanins.

-Last update: November 1997 / Patterns and text revised.

[ 1] Linzen B.
     "Blue blood: structure and evolution of hemocyanin."
     Naturwissenschaften 76:206-211(1989).
     PubMed=2664531
[ 2] Willott E., Wang X.-Y., Wells M.A.
     "cDNA and gene sequence of Manduca sexta arylphorin, an aromatic amino
     acid-rich larval serum protein. Homology to arthropod hemocyanins."
     J. Biol. Chem. 264:19052-19059(1989).
     PubMed=2808410
[ 3] Jones G., Brown N., Manczak M., Hiremath S., Kafatos F.C.
     "Molecular cloning, regulation, and complete sequence of a
     hemocyanin-related, juvenile hormone-suppressible protein from insect
     hemolymph."
     J. Biol. Chem. 265:8596-8602(1990).
     PubMed=2341396

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