Trypanosome histone variants H3.V and H4.V promote nucleosome plasticity in repressed chromatin

Submitted to SASBDB: 2025 Apr 2
Published in SASBDB: 2026 Jan 22

SASDX83 – T. brucei Canonical Nucleosome Core Particle

Histone H2AHistone H2BHistone H3, putativeHistone H4Widom 601 145 bp DNA - strand 1Widom 601 145 bp DNA - strand 2 experimental SAS data

Histone H2A Histone H2B Histone H3, putative Histone H4 Widom 601 145 bp DNA - strand 1 Widom 601 145 bp DNA - strand 2 Kratky plot

Sample:	Histone H2A, 28 kDa Trypanosoma brucei brucei … protein Histone H2B, 25 kDa Trypanosoma brucei brucei … protein Histone H3, putative, 29 kDa Trypanosoma brucei brucei … protein Histone H4, 22 kDa Trypanosoma brucei brucei … protein Widom 601 145 bp DNA - strand 1, 45 kDa DNA Widom 601 145 bp DNA - strand 2, 45 kDa DNA
Buffer:	20 mM HEPES, 150 mM NaCl, 1 mM DTT, pH: 7.5
Experiment:	SAXS data collected at B21, Diamond Light Source on 2023 Oct 10

R_g^Guinier	4.3	nm
D_max	11.8	nm
Volume^Porod	435	nm³

SASDX93 – T. brucei H3.V+H4.V Nucleosome Core Particle

Histone H2AHistone H2BWidom 601 145 bp DNA - strand 1Widom 601 145 bp DNA - strand 2Histone H3 variantHistone H4 experimental SAS data

Histone H2A Histone H2B Widom 601 145 bp DNA - strand 1 Widom 601 145 bp DNA - strand 2 Histone H3 variant Histone H4 Kratky plot

Sample:	Histone H2A, 28 kDa Trypanosoma brucei brucei … protein Histone H2B, 25 kDa Trypanosoma brucei brucei … protein Widom 601 145 bp DNA - strand 1, 45 kDa DNA Widom 601 145 bp DNA - strand 2, 45 kDa DNA Histone H3 variant, 32 kDa Trypanosoma brucei brucei … protein Histone H4, 22 kDa Trypanosoma brucei brucei … protein
Buffer:	20 mM HEPES, 150 mM NaCl, 1 mM DTT, pH: 7.5
Experiment:	SAXS data collected at B21, Diamond Light Source on 2023 Oct 10

R_g^Guinier	4.5	nm
D_max	13.1	nm
Volume^Porod	483	nm³

SASDXA3 – T. brucei H3.V-only Nucleosome Core Particle

Histone H2AHistone H2BHistone H4Widom 601 145 bp DNA - strand 1Widom 601 145 bp DNA - strand 2Histone H3 variant experimental SAS data

Histone H2A Histone H2B Histone H4 Widom 601 145 bp DNA - strand 1 Widom 601 145 bp DNA - strand 2 Histone H3 variant Kratky plot

Sample:	Histone H2A, 28 kDa Trypanosoma brucei brucei … protein Histone H2B, 25 kDa Trypanosoma brucei brucei … protein Histone H4, 22 kDa Trypanosoma brucei brucei … protein Widom 601 145 bp DNA - strand 1, 45 kDa DNA Widom 601 145 bp DNA - strand 2, 45 kDa DNA Histone H3 variant, 32 kDa Trypanosoma brucei brucei … protein
Buffer:	20 mM HEPES, 150 mM NaCl, 1 mM DTT, pH: 7.5
Experiment:	SAXS data collected at B21, Diamond Light Source on 2023 Oct 10

R_g^Guinier	4.4	nm
D_max	13.2	nm
Volume^Porod	481	nm³