PDBsum entry 1a04

Signal transduction protein

PDB id: 1a04

Contents

Protein chains

205 a.a. *

Waters ×361

* Residue conservation analysis

PDB id:

1a04

Name:

Signal transduction protein

Title:

The structure of the nitrate/nitrite response regulator protein narl in the monoclinic c2 crystal form

Structure:

Nitrate/nitrite response regulator protein narl. Chain: a, b. Fragment: residues 2 - 216 of the wild type narl. Engineered: yes

Source:

Escherichia coli. Organism_taxid: 562. Strain: jm109. Expressed in: escherichia coli. Expression_system_taxid: 562.

Resolution:

2.20Å R-factor: 0.211 R-free: 0.267

Authors:

I.Baikalov,I.Schroder,M.Kaczor-Grzeskowiak,D.Cascio,R.P.Gunsalus, R.E.Dickerson

Key ref:

I.Baikalov et al. (1998). NarL dimerization? Suggestive evidence from a new crystal form. Biochemistry, 37, 3665-3676. PubMed id: 9521685 DOI: 10.1021/bi972365a

Date:

08-Dec-97 Release date: 18-Mar-98

Protein chains

P0AF28  (NARL_ECOLI) -  Nitrate/nitrite response regulator protein NarL from Escherichia coli (strain K12)

Seq: 216 a.a.

Struc: 205 a.a.

Enzyme reactions

• Enzyme class: E.C.?

DOI no: 10.1021/bi972365a

Biochemistry 37:3665-3676 (1998)

PubMed id: 9521685

NarL dimerization? Suggestive evidence from a new crystal form.

I.Baikalov, I.Schröder, M.Kaczor-Grzeskowiak, D.Cascio, R.P.Gunsalus, R.E.Dickerson.

ABSTRACT

The structure of the Escherichia coli response regulator NarL has been solved in a new, monoclinic space group, and compared with the earlier orthorhombic crystal structure. Because the monoclinic crystal has two independent NarL molecules per asymmetric unit, we now have three completely independent snapshots of the NarL molecule: two from the monoclinic form and one from the orthorhombic. Comparison of these three structures shows the following: (a) The pairing of N and C domains of the NarL molecule proposed from the earlier analysis is in fact correct, although the polypeptide chain connecting domains was, and remains, disordered and not completely visible. The new structure exhibits identical relative orientation of N and C domains, and supplies some of the missing residues, leaving a gap of only seven amino acids. (b) Examination of corresponding features in the three independent NarL molecules shows that deformations in structure produced by crystal packing are negligible. (c) The "telephone receiver" model of NarL activation is confirmed. The N domain of NarL blocks the binding of DNA to the C domain that would be expected from the helix-turn-helix structure of the C domain. Hence, binding can only occur after significant displacement of N and C domains. (d) NarL monomers have a strong tendency toward dimerization involving contacts between helixes alpha 1 in the two monomers, and this may have mechanistic significance in DNA binding. Analogous involvement of helix alpha 1 in intermolecular contacts is also found in UhpA and in the CheY/CheZ complex.