Start2Fold

The database of hydrogen/deuterium exchange data on protein folding and stability

Entry STF0045

Protein A B-domain

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Protein information

Name of the protein: Immunoglobulin G-binding protein A
Organism: Staphylococcus aureus
Number of residues: 58
Related UniProt entry:   P38507 (Fragment: 212 - 270)
Related PDB entry:   1BDD

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Experiment sets

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STRONG

Method: Native exchange NMR

Conditions: pH 7.0; 20.0 Celsius; Probes: 28

Related publication:
 PMID 9232646

Experiment details: "Equilibrium hydrogen exchange experiments were performed by dissolving lyophilized protein directly in potassium phosphate buffer (100 mM, pH* 7.0) in D2O containing various concentrations (0 - 3.0 M) of GdmC1. The GdmCl solution in D2O was prepared by addition of a measured volume of D2O to a weighed sample of deuterated GdmCl. Exchange rates were measured by recording 1H-15N HSQC spectra as a function of time without removing the sample from the magnet."

Protection threshold: ΔG(op) > 6 kcal/mol

Sequence: TADNKFNKEQQNAFYEILHLPNLNEEQRNGFIQSLKDDPSQSANLLAEAKKLNDAQAPKA
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STRONG residues

28: R; 35: L; 49: A; 50: K; 51: K;
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EARLY

Method: Pulse labeling HDX NMR

Conditions: pH 5.0; 5.0 Celsius; Probes: 20

Related publication:
 PMID 9232646

Experiment details: "Pulsed H/D exchange measurements were performed at 5 °C. The B-domain of protein A at a concentration of about 3 mg/mL was first unfolded in 6.0 M GdmC1 at pH 5.0 using 10 mM sodium acetate buffer in H2O. Folding was initiated by six times dilution with D2O buffer at pH* 5.0 and was allowed to continue for 6 ms before the labeling pulse was applied for 10 ms. The pulse buffer contained 0.5 M Tris adjusted to pH* 11.5 using KOD. This leads to a pulse of pH* 10.5 after mixing with the folding buffer. The exchange was quenched by D2O buffer containing 0.5 M Tris and 100 mM acetic acid at pH* 0.5. The final pH* of the solution was 4.8 after the quench."

Protection threshold: proton occupancy > 0.7 at 6 ms refolding time

Sequence: TADNKFNKEQQNAFYEILHLPNLNEEQRNGFIQSLKDDPSQSANLLAEAKKLNDAQAPKA
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EARLY residues

14: F; 15: Y; 16: E; 17: I; 18: L; 20: L; 22: N; 23: L; 28: R; 29: N; 31: F; 34: S; 35: L; 36: K; 47: A; 48: E; 49: A; 50: K; 51: K; 52: L;
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