Table 2.

Examples of SAXS-based titrations or screening

System	Source	Type	Description and notes
Protein conformational change
Leucine/Isoleucine/Valine	Olah et al. (1993)	titration	contraction of bi-lobe domain upon ligand binding.
binding protein			Early example using lab-based source.
Transient photoexcitation	Cammarata et al. (2008)	time-resolved SAXS	laser-triggered detachment of carbon monoxide
of haemoglobin			enables solution characterisation of the relaxed
			state(s).
Aspartate transcarbamoylase	Cardia et al. (2008),	time-resolved SAXS	self-regulation of enzyme by substrates and
	Kantrowitz (2012)		regulators
Protein domain assembly
B12-dependent	Ando et al. (2012)	titration	association of two domains in a mixture of 1:1 and
methyltransferase			2:1 stoichiometry
Ribonucleotide reductase	Ando et al. (2016)	titration	$\alpha$ subunit in dimer-hexamer equilibrium, and $\beta$
			subunit dimer
Antibody self-association	Fukuda et al. (2017); Tian et al. (2014)	screening	technical studies on antibody stability as a function
			of concentration, pH, buffers and viscosity,
			important in clinical applications
Linker-connected domain configurations
Src kinase	Jamros et al. (2010); Yang et al. (2010)	two-point measurement	Assembly state of regulatory domains in the
			presence of SH3 signal peptide
Sxl-lethal RNA-binding	Chen et al. (2018)	titration	Equilibrium between apo-protein, 1:1 protein-
protein			RNA complex, and 2:2 protein-RNA complex.
Disordered protein interactions
Proliferating Cell	Cordeiro et al. (2017)	titration and population	association of trimer-of-dimer PCNA with
Nuclear Antigen, p15PAF		modelling	disordered p15 in 3:0–3:3 stoichiometries
α-synuclein	Herranz-Trillo et al. (2017)	time-resolved SAXS and	decomposition of species during amyloid fibril
		population modelling	genesis
Micellular compositions
various detergents used in	Lipfert et al. (2007),	titration	Shift in micellular size distributions and
membrane protein solubilisation	Oliver et al. (2013)		associated shape.
Nucleic-acid conformations
dT30 with MgCl2	Meisburger et al. (2013)	titration	Alteration of polymer properties due to
			coordinating ions.