The domain within your query sequence starts at position 3 and ends at position 1310; the E-value for the Med23 domain shown below is < 1e-12.

PMETQLQSIFEEVVKTEIIEEAFPGMFMDTPEDEKTKLISCLAAFRQFWSGLSQESHEQC
VQWIVKFIHGQHSPKRISFLYDCLAMAVETGLLPPRMVCESLINSDSLEWERTQLWALTF
KLVRKIIGGVDYKGVRDLLKAILEKILTIPNTVSSAVVQQLLAAREVIAYILERNACLLP
AYFAVTEIRKLYPEGKLPHWLLGNLVSDFVDTFRPTARINSICGRCSLLPVVNNSGAICN
SWKLDPATLRFPLKGLLPYDKDLFEPQTALLRYVLEQPYSRDMVCNMLGLNKQHKQRCPV
LEDQLVDLVVYAMERSETEEKFDDGGTSQLLWQHLSSQLIFFVLFQFASFPHMVLSLHQK
LAGRGLIKGRDHLMWVLLQFISGSIQKNALADFLPVMKLFDLLYPEKECIPVPDINKPQS
THAFAMTCIWIHLNRKAQNGDSTLQIPIPHSLKLHHEFLQQSLRNKSLQMNDYKIALLCN
AYSTNSECFTLPMGALVETIYGNGIMRVPLPGTSCLASASVTPLPMNLLDSLTVHAKMSL
IHSIATRVIKLAHTKSSVALAPALVETYSRLLVYMEIESLGIKGFISQLLPTVFKSHAWG
ILHTLLEMFSHRMHHIQPHYRVQLLSHLHTLAAVAQTNQNQLHLCVESTALRLITALGSS
EVQPQFTRFLNDPKTVLSAESEELNRALILTLARATHVTDFFTGSDSIQGTWCKDILQTI
MNFTPHNWASHTLSCFPAPLQAFFKQNNVPQESRFNLKKNVEEEYRKWKSMTDENEIITQ
FSVQGFPPLFLCLLWKMLLETDHISQIGYKVLERIGARALVAHVRTFADFLVYEFSTSAG
GQQLNKCIEILNDMVWKYNIVTLDRLILCLAMRSHEGNEAQVCYFIIQLLLLKPNDFRNR
VSDFVKENSPEHWLQSDWHTKHMSYHKKYPEKLYFEGLAEQVDPPVPIQSPYLPIYFGNV
CLRFLPVFDIVIHRFLELLPVSKSLETLLDHLGGLYKFHDRPVTYLYNTLHYYEMCLRNR
DHLKRKLVHAIIGSLKDNRPQGWCLSDTYLKHAMNAREDNPWVPEDSYYCKLIGRLVDTM
AGKSPGPFPNCDWRFNEFPNPAAHALHVTCVELMALAVPGKDVGNALLNVVLKSQPLVPR
ENITAWMNAIGLIITALPEPYWIVLHDRIVNVISSSSLTSETEWVGYPFRLFDFTACHQS
YSEMSCSYTLALAHAVWHHSSIGQLSLIPKFLTEALLPVVKTEFQLLYVYHLVGPFLQRF
QQERTRCMIEIGVAFYDMLLNVDQCSTHLNYMDPICDFLYHMKYMFTG

Med23

Med23
PFAM accession number:PF11573
Interpro abstract (IPR021629):

Med23 is one of the subunits of the Tail portion of the Mediator complex that regulates RNA polymerase II activity. Med23 is required for heat-shock-specific gene expression, and has been shown to mediate transcriptional activation of E1A in mice.

This is a PFAM domain. For full annotation and more information, please see the PFAM entry Med23