ID   B4_XENLA                Reviewed;         273 AA.
AC   P15308; Q6LEB8;
DT   01-APR-1990, integrated into UniProtKB/Swiss-Prot.
DT   01-APR-1990, sequence version 1.
DT   25-MAY-2022, entry version 91.
DE   RecName: Full=Protein B4;
DE   AltName: Full=Histone H1-like protein;
DE   AltName: Full=Linker histone B4;
GN   Name=b4;
OS   Xenopus laevis (African clawed frog).
OC   Eukaryota; Metazoa; Chordata; Craniata; Vertebrata; Euteleostomi; Amphibia;
OC   Batrachia; Anura; Pipoidea; Pipidae; Xenopodinae; Xenopus; Xenopus.
OX   NCBI_TaxID=8355;
RN   [1]
RP   NUCLEOTIDE SEQUENCE [MRNA], SUBCELLULAR LOCATION, AND DEVELOPMENTAL STAGE.
RC   TISSUE=Egg;
RX   PubMed=3060404; DOI=10.1101/gad.2.10.1284;
RA   Smith R.C., Dworkin-Rastl E., Dworkin M.B.;
RT   "Expression of a histone H1-like protein is restricted to early Xenopus
RT   development.";
RL   Genes Dev. 2:1284-1295(1988).
RN   [2]
RP   NUCLEOTIDE SEQUENCE [GENOMIC DNA] OF 1-21.
RC   TISSUE=Skeletal muscle;
RX   PubMed=8206379; DOI=10.1016/0378-1119(94)90102-3;
RA   Cho H., Wolffe A.P.;
RT   "Xenopus laevis B4, an intron-containing oocyte-specific linker histone-
RT   encoding gene.";
RL   Gene 143:233-238(1994).
RN   [3]
RP   INTERACTION WITH NAP1L1.
RX   PubMed=15928086; DOI=10.1073/pnas.0500822102;
RA   Shintomi K., Iwabuchi M., Saeki H., Ura K., Kishimoto T., Ohsumi K.;
RT   "Nucleosome assembly protein-1 is a linker histone chaperone in Xenopus
RT   eggs.";
RL   Proc. Natl. Acad. Sci. U.S.A. 102:8210-8215(2005).
CC   -!- SUBUNIT: Interacts with nap1l1. {ECO:0000269|PubMed:15928086}.
CC   -!- SUBCELLULAR LOCATION: Nucleus {ECO:0000255|PROSITE-ProRule:PRU00837,
CC       ECO:0000269|PubMed:3060404}. Chromosome {ECO:0000255|PROSITE-
CC       ProRule:PRU00837, ECO:0000269|PubMed:3060404}.
CC   -!- DEVELOPMENTAL STAGE: Expressed maternally. Abundant in oocytes, with
CC       expression levels remaining constant during the blastula stage.
CC       Expression starts to decline during the gastrula stage and is barely
CC       detectable by the neurula stage. {ECO:0000269|PubMed:3060404}.
CC   -!- SIMILARITY: Belongs to the histone H1/H5 family. {ECO:0000255|PROSITE-
CC       ProRule:PRU00837}.
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DR   EMBL; X13855; CAA32067.1; -; mRNA.
DR   EMBL; M36655; AAA49739.1; -; mRNA.
DR   EMBL; L22845; AAA20678.2; -; Genomic_DNA.
DR   PIR; A31215; A31215.
DR   PDB; 7KBF; EM; 4.42 A; K=1-273.
DR   PDBsum; 7KBF; -.
DR   AlphaFoldDB; P15308; -.
DR   SMR; P15308; -.
DR   Proteomes; UP000186698; Genome assembly.
DR   GO; GO:0000786; C:nucleosome; IEA:InterPro.
DR   GO; GO:0005634; C:nucleus; IDA:UniProtKB.
DR   GO; GO:0003677; F:DNA binding; IEA:UniProtKB-KW.
DR   GO; GO:0006334; P:nucleosome assembly; IEA:InterPro.
DR   CDD; cd00073; H15; 1.
DR   Gene3D; 1.10.10.10; -; 1.
DR   InterPro; IPR005818; Histone_H1/H5_H15.
DR   InterPro; IPR036388; WH-like_DNA-bd_sf.
DR   InterPro; IPR036390; WH_DNA-bd_sf.
DR   Pfam; PF00538; Linker_histone; 1.
DR   SMART; SM00526; H15; 1.
DR   SUPFAM; SSF46785; SSF46785; 1.
DR   PROSITE; PS51504; H15; 1.
PE   1: Evidence at protein level;
KW   3D-structure; Chromosome; Developmental protein; DNA-binding; Nucleus;
KW   Reference proteome; Repeat.
FT   CHAIN           1..273
FT                   /note="Protein B4"
FT                   /id="PRO_0000196002"
FT   DOMAIN          40..118
FT                   /note="H15"
FT                   /evidence="ECO:0000255|PROSITE-ProRule:PRU00837"
FT   REPEAT          189..198
FT                   /note="1"
FT   REPEAT          199..208
FT                   /note="2"
FT   REPEAT          209..217
FT                   /note="3"
FT   REGION          1..24
FT                   /note="Disordered"
FT                   /evidence="ECO:0000256|SAM:MobiDB-lite"
FT   REGION          120..273
FT                   /note="Disordered"
FT                   /evidence="ECO:0000256|SAM:MobiDB-lite"
FT   REGION          189..217
FT                   /note="3 X 10 AA tandem repeats"
FT   COMPBIAS        139..265
FT                   /note="Basic and acidic residues"
FT                   /evidence="ECO:0000256|SAM:MobiDB-lite"
SQ   SEQUENCE   273 AA;  29310 MW;  E8DD2C7838FED1EE CRC64;
     MAPKKAVAAP EGGNKENAAV KGSSKVKVKR KSIKLVKTQS HPPTLSMVVE VLKKNTERKG
     TSVQAIRTRI LSAHPTVDPL RLKFLLRTAL NKGLEKGILI RPLNSSATGA TGRFKLAKPV
     KTTKAGKENV ASENVDPNAE QETQKKAPKK EKKAKTEKEP KGEKTKAVAK KAKEDSDEKP
     KVAKSKKDKE AKEVDKANKE AKEVDKANKE AKEVDKAPAK KPKAKTEAAK AEGGGKAKKE
     PPKAKAKDVK AQKDSTDEGA PVKAGKKGKK VTN