ID   HGBB_HAEIF              Reviewed;        1067 AA.
AC   Q9KIV1;
DT   29-AUG-2001, integrated into UniProtKB/Swiss-Prot.
DT   01-OCT-2000, sequence version 1.
DT   03-AUG-2022, entry version 81.
DE   RecName: Full=Hemoglobin and hemoglobin-haptoglobin-binding protein B;
DE            Short=Hemoglobin-binding protein B;
DE   Flags: Precursor;
GN   Name=hgbB;
OS   Haemophilus influenzae.
OC   Bacteria; Proteobacteria; Gammaproteobacteria; Pasteurellales;
OC   Pasteurellaceae; Haemophilus.
OX   NCBI_TaxID=727;
RN   [1]
RP   NUCLEOTIDE SEQUENCE [GENOMIC DNA].
RC   STRAIN=NTHi N182;
RX   PubMed=10858226; DOI=10.1128/iai.68.7.4092-4101.2000;
RA   Cope L.D., Hrkal Z., Hansen E.J.;
RT   "Detection of phase variation in expression of proteins involved in
RT   hemoglobin and hemoglobin-haptoglobin binding by nontypeable Haemophilus
RT   influenzae.";
RL   Infect. Immun. 68:4092-4101(2000).
CC   -!- FUNCTION: Acts as a receptor for hemoglobin or the
CC       hemoglobin/haptoglobin complex of the human host and is required for
CC       heme uptake.
CC   -!- SUBCELLULAR LOCATION: Cell outer membrane.
CC   -!- MISCELLANEOUS: This protein is subject to phase-variable expression
CC       associated with alteration in the length of the CCAA repeat region.
CC       This mechanism is called slipped-strand mispairing. Addition or loss of
CC       CCAA repeat units would change the reading frame and result in
CC       introduction of stop codons downstream of the repeat region. This may
CC       be a mechanism of regulation and a way to avoid the immunological
CC       response of the host.
CC   -!- SIMILARITY: Belongs to the TonB-dependent receptor family.
CC       Hemoglobin/haptoglobin binding protein subfamily. {ECO:0000305}.
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DR   EMBL; AF221059; AAF80177.1; -; Genomic_DNA.
DR   AlphaFoldDB; Q9KIV1; -.
DR   GO; GO:0009279; C:cell outer membrane; IEA:UniProtKB-SubCell.
DR   GO; GO:0016021; C:integral component of membrane; IEA:UniProtKB-KW.
DR   GO; GO:0022857; F:transmembrane transporter activity; IEA:InterPro.
DR   GO; GO:0006811; P:ion transport; IEA:UniProt.
DR   GO; GO:0071702; P:organic substance transport; IEA:UniProt.
DR   Gene3D; 2.170.130.10; -; 1.
DR   Gene3D; 2.40.170.20; -; 2.
DR   InterPro; IPR039426; BtuB-like.
DR   InterPro; IPR012910; Plug_dom.
DR   InterPro; IPR037066; Plug_dom_sf.
DR   InterPro; IPR006970; PT.
DR   InterPro; IPR000531; TonB-dep_rcpt_b-brl.
DR   InterPro; IPR010949; TonB_Hb/transfer/lactofer_rcpt.
DR   InterPro; IPR036942; TonB_rcpt_b-brl_sf.
DR   InterPro; IPR010917; TonB_rcpt_CS.
DR   PANTHER; PTHR30069; PTHR30069; 1.
DR   Pfam; PF07715; Plug; 1.
DR   Pfam; PF04886; PT; 1.
DR   Pfam; PF00593; TonB_dep_Rec; 1.
DR   TIGRFAMs; TIGR01786; TonB-hemlactrns; 1.
DR   PROSITE; PS01156; TONB_DEPENDENT_REC_2; 1.
PE   3: Inferred from homology;
KW   Cell outer membrane; Membrane; Receptor; Repeat; Signal; TonB box;
KW   Transmembrane; Transmembrane beta strand; Transport.
FT   SIGNAL          1..24
FT                   /evidence="ECO:0000255"
FT   CHAIN           25..1067
FT                   /note="Hemoglobin and hemoglobin-haptoglobin-binding
FT                   protein B"
FT                   /id="PRO_0000034782"
FT   REPEAT          26..29
FT                   /note="1"
FT   REPEAT          30..33
FT                   /note="2"
FT   REPEAT          34..37
FT                   /note="3"
FT   REPEAT          38..41
FT                   /note="4"
FT   REPEAT          42..45
FT                   /note="5"
FT   REPEAT          46..49
FT                   /note="6"
FT   REGION          26..53
FT                   /note="Disordered"
FT                   /evidence="ECO:0000256|SAM:MobiDB-lite"
FT   REGION          26..49
FT                   /note="6 X 4 AA tandem repeats of Q-P-T-N"
FT   MOTIF           59..66
FT                   /note="TonB box"
FT   MOTIF           1050..1067
FT                   /note="TonB C-terminal box"
SQ   SEQUENCE   1067 AA;  122472 MW;  29D295DC4747632E CRC64;
     MTNFKFSLLA CSIAFALNAS TAYAAQPTNQ PTNQPTNQPT NQPTNQPTNQ NSNVSEQLEQ
     INVSGSSENI NIKEKKVGET QISAKKLAKQ QASDSRDLVR YETGITVVET GRTGASGYAV
     RGVDENRVGI MVDGLRQAET LSSQGFKELF EGYGNFNNTR NSIEIENVKT ATITKGADSL
     KSGSGALGGS VIFETKDARD YLIDKDYYLS YKRGYQTMNN QNLKTLTLAG RSKKFDILVV
     DTKRDGHEIE NYDYKIYPNK QADLRAVGPT REKADPYQIT RQSTLIKLGF QPNENHRLSV
     ALDDSTLETK GIDLSYALRP YSTAGNEKYG ERIINDQSKR KNIQFSYENF SQTPFWDHIK
     LSYSSQKITN KARSDEYCHQ STCPGVRNPQ GLHLVEKDGT YRIVDKDNND FHYKKDDSDL
     WAWGKELHNS KGKKISDDVD TKGGSLDSVL INCEKLDCSK RFRIYQEYDE NSSEKYTYDD
     REIKVETLPN GKKYGKIPLK KGEKLFSQEE ARFLFPKSHG YSTDFVNDRD LNTHTQQIKL
     DLDKEFHLWH TQHQLKYGGL YEKTLKSMVN HQYNTAANVQ WWADYFFCAR QEGGNLGGEK
     KPRPDISVAG CANGTLLHSD IGKDTYLIPV TTKNNVLYFG DNVQLTSWLG LDLNYRYDHV
     KYLPSYDKNI PVPKGLITGL FKKFKSTDYV YGKKYSKPDG YTDCTYDTPC YKQNFKDNLA
     LLLRKTDYKH HSYNLGLNLD PTDWLRVQLK YANGFRAPTS DEIYMTFKHP QFSIQPNTDL
     KAETSKTKEV AFTFYKNSSY ITLNAFQNDY RNFIDLVEVG ERPIEEDSVV RYPFHQNQNR
     DRARVRGIEI ASRLEIGDLF EKLQGFHLGY KFTYQKGRIK DNGLHPKYKE FLKLNKDQHP
     EYEAIARKPQ PMNALQPTTS VYNIGYDAPS QKWGVDMYIT NVAAKKAKDS FNSQWTSMVE
     RKEKQYTDIT DIKASKANGK EVKDSRGLWR NNRYTVIDTI AYWKPIKNLT FTAGVYNLTN
     KKYLTWDSAR SIRHIGTINR VKTETGKGLN RFYAPGRNYR MSVQFEF