4R5F

X-ray structure of the D199K mutant of the cysteine desulfurase IscS from A. fulgidus

Summary for 4R5F

• Entry DOI: 10.2210/pdb4r5f/pdb
• Related: 4EB5 4EB7 4HVK
• Descriptor: Cysteine desulfurase IscS 2, CALCIUM ION, CHLORIDE ION, ... (7 entities in total)
• Functional Keywords: metal binding protein
• Biological source: Archaeoglobus fulgidus DSM 4304
• Total number of polymer chains: 1
• Total formula weight: 44073.54

Authors

Pagnier, A.,Nicolet, Y.,Fontecilla-Camps, J.C. (deposition date: 2014-08-21, release date: 2014-12-17, Last modification date: 2023-09-20)

Primary citation

Pagnier, A.,Nicolet, Y.,Fontecilla-Camps, J.C.
IscS from Archaeoglobus fulgidus has no desulfurase activity but may provide a cysteine ligand for [Fe2S2] cluster assembly.
Biochim.Biophys.Acta, 1853:1457-1463, 2015

PubMed Abstract: Iron sulfur ([Fe-S]) clusters are essential prosthetic groups involved in fundamental cell processes such as gene expression regulation, electron transfer and Lewis acid base chemistry. Central components of their biogenesis are pyridoxal-5'-phosphate (PLP) dependent l-cysteine desulfurases, which provide the necessary S atoms for [Fe-S] cluster assembly. The archaeon Archaeoglobus fulgidus (Af) has two ORFs, which although annotated as l-cysteine desulfurases of the ISC type (IscS), lack the essential Lys residue (K199 in Af) that forms a Schiff base with PLP. We have previously determined the structure of an Af(IscU-D35A-IscS)2 complex heterologously expressed in Escherichia coli and found it to contain a [Fe2S2] cluster. In order to understand the origin of sulfide in that structure we have performed a series of functional tests using wild type and mutated forms of AfIscS. In addition, we have determined the crystal structure of an AfIscS-D199K mutant. From these studies we conclude that: i) AfIscS has no desulfurase activity; ii) in our in vitro [Fe2S2] cluster assembly experiments, sulfide ions are non-enzymatically generated by a mixture of iron, l-cysteine and PLP and iii) the physiological role of AfIscS may be to provide a cysteine ligand to the nascent cluster as observed in the [Fe2S2]-Af(IscU-D35A-IscS)2 complex. This article is part of a Special Issue entitled: Fe/S proteins: Analysis, structure, function, biogenesis and diseases.

PubMed: 25447670
DOI: 10.1016/j.bbamcr.2014.10.015

Experimental method

X-RAY DIFFRACTION (1.9 Å)