The domain within your query sequence starts at position 50 and ends at position 377; the E-value for the 3t99 domain shown below is < 1e-12.

PPEPQIIVGICAMTKKSKSKPMTQILERLCRFDYLTVVILGEDVILNEPVENWPSCHCLI
SFHSKGFPLDKAVAYSKLRNPFLINDLAMQYYIQDRREVYRILQEEGIDLPRYAVLNRDP
ACPEECSLIEGEDQVEVNGAVFPKPFVEKPVSAEDHNVYIYYPSSAGGGSQRLFRKIGSR
SSVYSPESSVRKTGSYIYEEFMPTDGTDVKVYTVGPDYAHAEARKSPALDGKVERDSEGK
EVRYPVMLTAMEKLVARKVCVAFKQTVCGFDLLRANGHSFVCDVNGFSFVKNSMKYYDDC
AKILGNTIMRELAPQFQIPWSIPTEAED

This is a PDB domain - please see the PDBSUM entry of 3t99 for further annotation