The domain within your query sequence starts at position 23 and ends at position 51; the E-value for the Sushi domain shown below is 6.7e-6.

CPKPDDLPFATVVPLKTSYDPGEQIVYSC

Sushi

Sushi
PFAM accession number:PF00084
Interpro abstract (IPR000436):

The extracellular sushi domain is characterised by a consensus sequence spanning ~60 residues containing four invariant cysteine residues forming two disulfide-bridges (I-III and II-IV), a highly conserved tryptophan, and conserved glycine, proline, and hydrophobic residues [ (PUBMED:2751824) ]. Sushi domains are known to be involved in many recognition processes, including the binding of several complement factors to fragments C3b and C4b [ (PUBMED:2751824) ]. The sushi domain is also known as the complement controle protein (CCP) module or the short consensus repeat (SCR).

Several structure of the sushi domain have been solved (see for example {PDB:1HCC}) [ (PUBMED:1829116) ]. The sushi domain folds into a small and compact hydrophobic core enveloped by six beta-strands and stabilised by two disulfide bridges. The relative structural orientation of the Beta-2 and Beta-4 strands is shared by all the sushi structures, whereas the topology of the other strands relative to this central conserved core is variable, especially at the regions that form the interfaces with the preceding and following domains [ (PUBMED:10775260) ].

This is a PFAM domain. For full annotation and more information, please see the PFAM entry Sushi