The domain within your query sequence starts at position 3 and ends at position 298; the E-value for the Na_K-ATPase domain shown below is 1.1e-100.

RGKAKEEGSWKKFIWNSEKKEFLGRTGGSWFKILLFYVIFYGCLAGIFIGTIQVMLLTIS
ELKPTYQDRVAPPGLTQIPQIQKTEISFRPNDPKSYEAYVLNIIRFLEKYKDSAQKDDMI
FEDCGNVPSEPKERGDINHERGERKVCRFKLDWLGNCSGLNDDSYGYREGKPCIIIKLNR
VLGFKPKPPKNESLETYPLMMKYNPNVLPVQCTGKRDEDKDKVGNIEYFGMGGYYGFPLQ
YYPYYGKLLQPKYLQPLLAVQFTNLTVDTEIRVECKAYGENIGYSEKDRFQGRFDV

Na_K-ATPase

Na_K-ATPase
PFAM accession number:PF00287
Interpro abstract (IPR000402):

This entry represents the sodium/potassium-transporting ATPase subunit beta. This is the non-catalytic component of the active enzyme, which catalyses the hydrolysis of ATP coupled with the exchange of Na + and K + ions across the plasma membrane. The beta subunit regulates, through assembly of alpha/beta heterodimers, the number of sodium pumps transported to the plasma membrane [ (PUBMED:9648860) ].

GO process:potassium ion transport (GO:0006813), sodium ion transport (GO:0006814)
GO component:sodium:potassium-exchanging ATPase complex (GO:0005890)

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