The domain within your query sequence starts at position 353 and ends at position 435; the E-value for the RPT_1 domain shown below is 2.35e-20.

GSVLTMGSVLTAGAVLTAGAVLTMGSVLTAGSVLTAGAVLTAGSVLTMGSVLTAGAVLTM
GSVLTAGSVLTAGSVLTAGSVLT

This is a significant internal repeat in the query protein sequence, as detected by the Prospero program.