SASDAV6: Cysteine desulfurase IscS dimer (Cysteine desulfurase IscS)

Basic information

• Entry: Database: SASBDB / ID: SASDAV6

Sample

Cysteine desulfurase IscS dimer

• Cysteine desulfurase IscS (protein), Escherichia coli

Function / homology

Function:

IscS-TusA complex / oxazole or thiazole biosynthetic process / tRNA 4-thiouridine biosynthesis / IscS-IscU complex / sulfur compound transport / sulfurtransferase complex / selenocysteine catabolic process / sulfur carrier activity / tRNA wobble position uridine thiolation / detection of UV / selenocysteine lyase activity / L-cysteine desulfurase complex / cysteine desulfurase / cysteine desulfurase activity / L-cysteine catabolic process / thiamine biosynthetic process / [2Fe-2S] cluster assembly / iron-sulfur cluster assembly / 2 iron, 2 sulfur cluster binding / pyridoxal phosphate binding / metal ion binding / cytosol

Domain/homology:

Cysteine desulfurase IscS / Cysteine desulfurase / Aminotransferase class-V, pyridoxal-phosphate binding site / Aminotransferases class-V pyridoxal-phosphate attachment site. / Aminotransferase class V domain / Aminotransferase class-V / Pyridoxal phosphate-dependent transferase, small domain / Pyridoxal phosphate-dependent transferase, major domain / Pyridoxal phosphate-dependent transferase

Component:

Cysteine desulfurase IscS

• Biological species: Escherichia coli (E. coli)
• Citation: Journal: Nat Commun / Year: 2010; Title: Structural bases for the interaction of frataxin with the central components of iron-sulphur cluster assembly.; Authors: Filippo Prischi / Petr V Konarev / Clara Iannuzzi / Chiara Pastore / Salvatore Adinolfi / Stephen R Martin / Dmitri I Svergun / Annalisa Pastore / ; Abstract: Reduced levels of frataxin, an essential protein of as yet unknown function, are responsible for causing the neurodegenerative pathology Friedreich's ataxia. Independent reports have linked frataxin to iron-sulphur cluster assembly through interactions with the two central components of this machinery: desulphurase Nfs1/IscS and the scaffold protein Isu/IscU. In this study, we use a combination of biophysical methods to define the structural bases of the interaction of CyaY (the bacterial orthologue of frataxin) with the IscS/IscU complex. We show that CyaY binds IscS as a monomer in a pocket between the active site and the IscS dimer interface. Recognition does not require iron and occurs through electrostatic interactions of complementary charged residues. Mutations at the complex interface affect the rates of enzymatic cluster formation. CyaY binding strengthens the affinity of the IscS/IscU complex. Our data suggest a new paradigm for understanding the role of frataxin as a regulator of IscS functions.

Contact author

• Petr Konarev (EMBL-Hamburg, European Molecular Biology Laboratory (EMBL) - Hamburg outstation, Notkestraße 85, Geb. 25A, 22607 Hamburg, Deutschland, Germany)

Models

• Model #221: ; Type: atomic / Software: crysol / Radius of dummy atoms: 1.90 A / Symmetry: P2 / Chi-square value: 1.565001; Search similar-shape structures of this assembly by Omokage search (details)
• Model #222: ; Type: dummy / Software: DAMMIF / Radius of dummy atoms: 3.90 A / Chi-square value: 1.192464; Search similar-shape structures of this assembly by Omokage search (details)

Sample

• Sample: Name: Cysteine desulfurase IscS dimer / Specimen concentration: 2.5 mg/ml
• Buffer: Name: Tris-HClTris / Concentration: 20.00 mM / pH: 8 / Composition: 150 mM NaCl and 10 mM β-mercaptoethanol

Entity #135

Type: protein / Description: Cysteine desulfurase IscS / Formula weight: 43.597 / Num. of mol.: 2 / Source: Escherichia coli / References: UniProt: P0A6B7
Sequence:

KLPIYLDYSA TTPVDPRVAE KMMQFMTMDG TFGNPASRSH RFGWQAEEAV DIARNQIADL VGADPREIVF TSGATESDNL AIKGAANFYQ KKGKHIITSK TEHKAVLDTC RQLEREGFEV TYLAPQRNGI IDLKELEAAM RDDTILVSIM HVNNEIGVVQ DIAAIGEMCR ARGIIYHVDA TQSVGKLPID LSQLKVDLMS FSGHKIYGPK GIGALYVRRK PRVRIEAQMH GGGHERGMRS GTLPVHQIVG MGEAYRIAKE EMATEMERLR GLRNRLWNGI KDIEEVYLNG DLEHGAPNIL NVSFNYVEGE SLIMALKDLA VSSGSACTSA SLEPSYVLRA LGLNDELAHS SIRFSLGRFT TEEEIDYTIE LVRKSIGRLR DLSPLWEMYK Q

Experimental information

• Beam: Instrument name: DORIS III X33 / City: Hamburg / 国: Germany / Shape: 0.6 / Type of source: X-ray synchrotronSynchrotron / Wavelength: 0.15 Å / Dist. spec. to detc.: 2.7 mm
• Detector: Name: Pilatus 1M-W / Pixsize x: 0.172 mm

Scan

Title: s / Measurement date: Nov 5, 2009 / Storage temperature: 15 °C / Cell temperature: 15 °C / Exposure time: 30 sec. / Number of frames: 4 / Unit: 1/nm /

	Min	Max
Q	0.0775	6.237

Distance distribution function P(R)

Sofotware P(R): GNOM 4.5a / Number of points: 374 /

	Min	Max
Q	0.2242	3.209
P(R) point	55	428
R	0	10.89

Result

Type of curve: single_conc
Comments: Reduced levels of frataxin, an essential protein of as yet unknown function, are responsible for causing the neurodegenerative pathology Friedreich’s ataxia. Independent reports have linked frataxin to iron–sulphur cluster assembly through interactions with the two central components of this machinery: desulphurase Nfs1/IscS and the scaffold protein Isu/IscU. In this study, we use a combination of biophysical methods to define the structural bases of the interaction of CyaY (the bacterial orthologue of frataxin) with the IscS/IscU complex. We show that CyaY binds IscS as a monomer in a pocket between the active site and the IscS dimer interface. Recognition does not require iron and occurs through electrostatic interactions of complementary charged residues. Mutations at the complex interface affect the rates of enzymatic cluster formation. CyaY binding strengthens the affinity of the IscS/IscU complex. Our data suggest a new paradigm for understanding the role of frataxin as a regulator of IscS functions.

	Experimental	Standard
MW	92 kDa	92 kDa

	P(R)	Guinier	Guinier error
Forward scattering, I0	68	68	0.14
Radius of gyration, Rg	3.19 nm	3.2 nm	0.009

	Min	Max
D	-	10.9
Guinier point	54	-