1BK2

A-SPECTRIN SH3 DOMAIN D48G MUTANT

Summary for 1BK2

• Entry DOI: 10.2210/pdb1bk2/pdb
• Descriptor: A-SPECTRIN (2 entities in total)
• Functional Keywords: sh3-domain, cytoskeleton, calmodulin-binding, actin-binding
• Biological source: Gallus gallus (chicken)
• Cellular location: Cytoplasm, cytoskeleton: P07751
• Total number of polymer chains: 1
• Total formula weight: 6637.66

Authors

Martinez, J.C.,Pisabarro, M.T.,Serrano, L. (deposition date: 1998-07-14, release date: 1999-02-16, Last modification date: 2024-05-22)

Primary citation

Martinez, J.C.,Pisabarro, M.T.,Serrano, L.
Obligatory steps in protein folding and the conformational diversity of the transition state.
Nat.Struct.Biol., 5:721-729, 1998

PubMed Abstract: We have analyzed the existence of obligatory steps in the folding reaction of the alpha-spectrin SH3 domain by mutating Asp 48 (D48G), which is at position i+3 of an isolated two-residue type II' beta-turn. Calorimetry and X-ray analysis show an entropic stabilizing effect resulting from local changes at the dihedral angles of the beta-turn. Kinetic analysis of D48G shows that this beta-turn is fully formed in the transition state, while there is no evidence of its formation in an isolated fragment. Introduction of several mutations in the D48G protein reveals that the local stabilization has not significantly altered the transition state ensemble. All these results, together with previous analysis of other alpha-spectrin and src SH3 mutants, indicate that: (i) in the folding reaction there could be obligatory steps which are not necessarily part of the folding nucleus; (ii) transition state ensembles in beta-sheet proteins could be quite defined and conformationally restricted ('mechanic folding nucleus'); and (iii) transition state ensembles in some proteins could be evolutionarily conserved.

PubMed: 9699637
DOI: 10.1038/1418

Experimental method

X-RAY DIFFRACTION (2.01 Å)