PDBsum entry 4i0b

Transcription

PDB id: 4i0b

Contents

Protein chains

199 a.a.

Ligands

CMP ×3

Waters ×331

PDB id:

4i0b

Name:

Transcription

Title:

Structure of the mutant catabolite gene activator protein h160l

Structure:

Catabolite gene activator. Chain: a, b. Synonym: camp receptor protein, camp regulatory protein. Engineered: yes. Mutation: yes

Source:

Escherichia coli. Organism_taxid: 83333. Strain: k12. Gene: crp, cap, csm, b3357, jw5702. Expressed in: escherichia coli. Expression_system_taxid: 562

Resolution:

1.50Å R-factor: 0.182 R-free: 0.208

Authors:

E.Pohl,P.D.Townsend,T.Rodgers,D.Burnell,T.C.B.Mcleish,M.R.Wilson, M.J.Cann

Key ref:

T.L.Rodgers et al. (2013). Modulation of global low-frequency motions underlies allosteric regulation: demonstration in CRP/FNR family transcription factors. Plos Biol, 11, e1001651. PubMed id: 24058293 DOI: 10.1371/journal.pbio.1001651

Date:

16-Nov-12 Release date: 30-Oct-13

Protein chains

P0ACJ8  (CRP_ECOLI) -  DNA-binding transcriptional dual regulator CRP from Escherichia coli (strain K12)

Seq: 210 a.a.

Struc: 199 a.a.*

* PDB and UniProt seqs differ at 1 residue position (black cross)

Enzyme reactions

• Enzyme class: E.C.?

DOI no: 10.1371/journal.pbio.1001651

Plos Biol 11:e1001651 (2013)

PubMed id: 24058293

Modulation of global low-frequency motions underlies allosteric regulation: demonstration in CRP/FNR family transcription factors.

T.L.Rodgers, P.D.Townsend, D.Burnell, M.L.Jones, S.A.Richards, T.C.McLeish, E.Pohl, M.R.Wilson, M.J.Cann.

ABSTRACT

Allostery is a fundamental process by which ligand binding to a protein alters its activity at a distinct site. There is growing evidence that allosteric cooperativity can be communicated by modulation of protein dynamics without conformational change. The mechanisms, however, for communicating dynamic fluctuations between sites are debated. We provide a foundational theory for how allostery can occur as a function of low-frequency dynamics without a change in structure. We have generated coarse-grained models that describe the protein backbone motions of the CRP/FNR family transcription factors, CAP of Escherichia coli and GlxR of Corynebacterium glutamicum. The latter we demonstrate as a new exemplar for allostery without conformation change. We observe that binding the first molecule of cAMP ligand is correlated with modulation of the global normal modes and negative cooperativity for binding the second cAMP ligand without a change in mean structure. The theory makes key experimental predictions that are tested through an analysis of variant proteins by structural biology and isothermal calorimetry. Quantifying allostery as a free energy landscape revealed a protein "design space" that identified the inter- and intramolecular regulatory parameters that frame CRP/FNR family allostery. Furthermore, through analyzing CAP variants from diverse species, we demonstrate an evolutionary selection pressure to conserve residues crucial for allosteric control. This finding provides a link between the position of CRP/FNR transcription factors within the allosteric free energy landscapes and evolutionary selection pressures. Our study therefore reveals significant features of the mechanistic basis for allostery. Changes in low-frequency dynamics correlate with allosteric effects on ligand binding without the requirement for a defined spatial pathway. In addition to evolving suitable three-dimensional structures, CRP/FNR family transcription factors have been selected to occupy a dynamic space that fine-tunes biological activity and thus establishes the means to engineer allosteric mechanisms driven by low-frequency dynamics.