histone-fold domain found in histone H4 and similar proteins; Histone H4 is a core component of the nucleosome, which wraps and compacts DNA into chromatin, limiting DNA accessibility to the cellular machineries which require DNA as a template. Histones thereby play a central role in transcription regulation, DNA repair, DNA replication, and chromosomal stability. DNA accessibility is regulated via a complex set of post-translational modifications of histones, also called the histone code, and nucleosome remodeling. The nucleosome is a histone octamer containing two molecules each of H2A, H2B, H3 and H4 assembled in one H3-H4 heterotetramer and two H2A-H2B heterodimers. The octamer wraps approximately 147 bp of DNA.

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                ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....
gi 17562018  22 VLRDNIQGITKPAIRRLARRGGVKRISGLIYEETRGVLKVFLENVIRDAVTYCEHAKRKTVTAMDVVYALKRQGRTLYG 100
Cdd:cd22912   1 VLRDNIQGITKPAIRRLARRGGVKRISGDIYEEVRGVLKDFLENVIRDAVTYTEHAKRKTVTAMDVVYALKRQGRTLYG 79

Archaeal histone H3/H4 [Chromatin structure and dynamics];

                        10        20        30        40        50        60
                ....*....|....*....|....*....|....*....|....*....|....*....|
gi 17562018  34 AIRRLARRGGVKRISGLIYEETRGVLKVFLENVIRDAVTYCEHAKRKTVTAMDVVYALKR 93
Cdd:COG2036   6 PVDRIIKKAGAERVSEDAVEALAEILEEYAEEIAKEAVELAKHAGRKTVKAEDIELAAKL 65

histone H4; Provisional

                         10        20        30        40        50        60        70        80
                 ....*....|....*....|....*....|....*....|....*....|....*....|....*....|....*....|
gi 17562018   18 RHRKVLRDNIQGITKPAIRRLARRGGVKRISGLIYEETRGVLKVFLENVIRDAVTYCEHAKRKTVTAMDVVYALKRQGRT 97
Cdd:PTZ00015  19 RQKKVLRDNIRGITKGAIRRLARRGGVKRISGDIYEEVRGVLKAFLENVVRDSTAYTEYARRKTVTAMDVVYALKRQGRT 98

                 ....
gi 17562018   98 LYGF 101
Cdd:PTZ00015  99 LYGF 102

Histone H4;

                           10        20        30        40        50        60        70
                   ....*....|....*....|....*....|....*....|....*....|....*....|....*....|...
gi 17562018     18 RHRKVLRDNIQGITKPAIRRLARRGGVKRISGLIYEETRGVLKVFLENVIRDAVTYCEHAKRKTVTAMDVVYA 90
Cdd:smart00417   2 RHKKVLRDNIQGITKPAIRRLARRGGVKRISGLIYDETRNVLKSFLENVVRDAVTYTEHARRKTVTAMDVVYA 74

histone-fold domain found in centromere protein T (CENP-T) and similar proteins; CENP-T, also called interphase centromere complex protein 22 (ICEN22), is a component of the CENPA-NAC (nucleosome-associated) complex, which plays a central role in the assembly of kinetochore proteins, mitotic progression, and chromosome segregation. The CENPA-NAC complex recruits the CENPA-CAD (nucleosome distal) complex and may be involved in incorporation of newly synthesized CENPA into centromeres. CENP-T is also part of a nucleosome-associated complex that binds specifically to histone H3-containing nucleosomes at the centromere, as opposed to nucleosomes containing CENPA. Moreover, CENP-T is a component of the heterotetrameric CENP-T-W-S-X complex that binds and supercoils DNA, and plays an important role in kinetochore assembly. CENP-T has a fundamental role in kinetochore assembly and function. It is one of the inner kinetochore proteins, with most further proteins binding downstream. It is required for normal chromosome organization and normal progress through mitosis.

                        10        20        30        40        50        60
                ....*....|....*....|....*....|....*....|....*....|....*....|....*..
gi 17562018  29 GITKPAIRRLARRGGVKRISGLIYEETRGVLKVFLENVIRDAVTYCEHAKRKTVTAMDVVYALKRQG 95
Cdd:cd22920   2 SLPKSLVKKLFKHFLKRRVSKEALEALEEISEEFFEQLSDDLEAYADHAGRKTINEKDVELLMKRQR 68

histone fold domain (HFD) superfamily; The histone fold domain (HFD) is a structurally conserved interaction motif involved in heterodimerization of the core histones and their assembly into the nucleosome octamer. Histone fold heterodimers play crucial roles in gene regulation. The minimal HFD consists of three alpha helices connected by two short, unstructured loops. The HFD is found in core histones, TATA box-binding protein-associated factors (TAFs), and many other transcription factors. HFD plays a role in the nucleosomal core particle by conserving histone interactions; these contain more than one HFD. The structure of the nucleosome core particle has two modes that have the largest interaction surfaces, and these are the H3-H4 and H2A-H2B heterodimer interactions. Several TAFs interact via histone-fold (HF) motifs. Five HF-containing TAF pairs have been described in transcription factor II D (TFIID): TAF6-TAF9, TAF4-TAF12, TAF11-TAF13, TAF8-TAF10 and TAF3-TAF10.

                        10        20        30        40        50        60
                ....*....|....*....|....*....|....*....|....*....|....*....|...
gi 17562018  30 ITKPAIRRLARRGGVKRISGLIYEETRGVLKVFLENVIRDAVTYCEHAKRKTVTAMDVVYALK 92
Cdd:cd00076   1 LLRSAVARILKSAGFDSVSKSALELLSDLLERYLEELARAAKAYAELAGRTTPNAEDVELALE 63

Centromere kinetochore component CENP-T histone fold; CENP-T is a family of vertebral kinetochore proteins that associates directly with CENP-W. The N-terminus of CENP-T proteins interacts directly with the Ndc80 complex in the outer kinetochore. Importantly, the CENP-T-W complex does not directly associate with CENP-A, but with histone H3 in the centromere region. CENP-T and -W form a hetero-tetramer with CENP-S and -X and bind to a ~100 bp region of nucleosome-free DNA forming a nucleosome-like structure. The DNA-CENP-T-W-S-X complex is likely to be associated with histone H3-containing nucleosomes rather than with CENP-nucleosomes. This domain is the C-terminal histone fold domain of CENP-T, which associates with chromatin.

                          10        20        30        40        50        60        70
                  ....*....|....*....|....*....|....*....|....*....|....*....|....*....|.
gi 17562018    32 KPAIRRLA----RRGGVK-RISGLIYEETRGVLKVFLENVIRDAVTYCEHAKRKTVTAMDVVYALKRQGRT 97
Cdd:pfam15511  10 TAVVKRLAqrfaRTSGSKgKLSKEALAALEQASDWFFEQMGEDLAAYAKHAGRKTIDESDVILLMKRQRQI 80

histone-fold domain found in transcription initiation factor TFIID subunit 9 (TAF9) and similar proteins; The family includes TAF9 (also called TATA Binding Protein (TBP) associated factor 9, RNA polymerase II TBP-associated factor subunit G, STAF31/32, transcription initiation factor TFIID 31 kDa subunit, TAFII-31, TAFII31, transcription initiation factor TFIID 32 kDa subunit, TAFII-32, or TAFII32) and TAF9-like (also called transcription initiation factor TFIID subunit 9B, neuronal cell death-related protein 7, DN-7, or transcription-associated factor TAFII31L), which are essential for cell viability. They are involved in transcriptional activation as well as the repression of distinct but overlapping sets of genes. They may have roles in gene regulation associated with apoptosis. Both TAF9 and TAF9-like are TAFs that are components of the transcription factor IID (TFIID) complex, the TBP-free TAFII complex (TFTC), the PCAF histone acetylase complex and the STAGA transcription coactivator-HAT complex. TFIID or TFTC are essential for the regulation of RNA polymerase II-mediated transcription. TAF9 interacts directly with different transcription factors such as p53, herpes simplex virus activator vp16, and the basal transcription factor TFIIB.

                        10        20        30        40        50        60        70
                ....*....|....*....|....*....|....*....|....*....|....*....|....*....|.
gi 17562018  34 AIRRLARRGGVKRisgliYEEtrGVLKVFLE-------NVIRDAVTYCEHAKRKTVTAMDVVYALKRQGRT 97
Cdd:cd07979   6 VIRAILKSMGVTD-----YEP--RVVNQLLEfayryttEVLQDAKVYAEHAGRSQIDEEDVRLAIQSRADH 69

CENP-S protein; CENP-S is a family of vertebral and fungal kinetochore component proteins. CENP-S complexes with CENP-X to form a stable CENP-T-W-S-X heterotetramer.

                          10        20        30
                  ....*....|....*....|....*....|.
gi 17562018    63 LENVIRDAVTYCEHAKRKTVTAMDVVYALKR 93
Cdd:pfam15630  42 LENLAKDLEAFAKHAGRSTITTDDVKLLARR 72