The key to the extraordinary thermal stability of P. furiosus holo-rubredoxin: iron binding-guided packing of a core aromatic cluster responsible for high kinetic stability of the native structure.

ABSTRACT: Pyrococcus furiosus rubredoxin (PfRd), a small, monomeric, 53 residues-long, iron-containing, electron-transfer protein of known structure is sometimes referred to as being the most structurally-stable protein known to man. Here, using a combination of mutational and spectroscopic (CD, fluorescence, and NMR) studies of differently made holo- and apo-forms of PfRd, we demonstrate that it is not the presence of iron, or even the folding of the PfRd chain into a compact well-folded structure that causes holo-PfRd to display its extraordinary thermal stability, but rather the correct iron binding-guided packing of certain residues (specifically, Trp3, Phe29, Trp36, and also Tyr10) within a tight aromatic cluster of six residues in PfRd's hydrophobic core. Binding of the iron atom appears to pl

SUBMITTER: Prakash S 

PROVIDER: S-EPMC3945938 | biostudies-literature | 2014

REPOSITORIES: biostudies-literature