6HUL

Sulfolobus solfataricus Tryptophan Synthase AB Complex

Summary for 6HUL

• Entry DOI: 10.2210/pdb6hul/pdb
• Descriptor: Tryptophan synthase alpha chain, Tryptophan synthase beta chain 1, SN-GLYCEROL-3-PHOSPHATE, ... (8 entities in total)
• Functional Keywords: tryptophan synthase plp, lyase
• Biological source: Sulfolobus solfataricus; More
• Total number of polymer chains: 2
• Total formula weight: 75759.51

Authors

Fleming, J.R.,Mayans, O. (deposition date: 2018-10-08, release date: 2018-11-07, Last modification date: 2024-01-24)

Primary citation

Fleming, J.R.,Schupfner, M.,Busch, F.,Basle, A.,Ehrmann, A.,Sterner, R.,Mayans, O.
Evolutionary Morphing of Tryptophan Synthase: Functional Mechanisms for the Enzymatic Channeling of Indole.
J.Mol.Biol., 430:5066-5079, 2018

PubMed Abstract: Tryptophan synthase (TrpS) is a heterotetrameric αββα enzyme that exhibits complex substrate channeling and allosteric mechanisms and is a model system in enzymology. In this work, we characterize proposed early and late evolutionary states of TrpS and show that they have distinct quaternary structures caused by insertions-deletions of sequence segments (indels) in the β-subunit. Remarkably, indole hydrophobic channels that connect α and β active sites have re-emerged in both TrpS types, yet they follow different paths through the β-subunit fold. Also, both TrpS geometries activate the α-subunit through the rearrangement of loops flanking the active site. Our results link evolutionary sequence changes in the enzyme subunits with channeling and allostery in the TrpS enzymes. The findings demonstrate that indels allow protein quaternary architectures to escape "minima" in the evolutionary landscape, thereby overcoming the conservational constraints imposed by existing functional interfaces and being free to morph into new mechanistic enzymes.

PubMed: 30367843
DOI: 10.1016/j.jmb.2018.10.013

Experimental method

X-RAY DIFFRACTION (2.55 Å)