PDBsum entry 1zw8

Transcription

PDB id: 1zw8

Contents

Protein chain

64 a.a. *

Metals

_ZN ×2

* Residue conservation analysis

PDB id:

1zw8

Name:

Transcription

Title:

Solution structure of a zap1 zinc-responsive domain provides insights into metalloregulatory transcriptional repression in saccharomyces cerevisiae

Structure:

Zinc-responsive transcriptional regulator zap1. Chain: a. Fragment: two interacting zinc fingers. Engineered: yes. Mutation: yes

Source:

Saccharomyces cerevisiae. Baker's yeast. Organism_taxid: 4932. Gene: zap1. Expressed in: escherichia coli bl21. Expression_system_taxid: 511693. Other_details: zap1 gene derived from pyef2zap1. (Gift from d.J. Eide, university of wisconsin-madison). Zzf1-2 portion of gene cloned into pet-21a plasmid (novagen). Further details can be found

NMR struc:

20 models

Authors:

Z.Wang,L.S.Feng,K.Venkataraman,V.A.Matskevich,P.Parasuram,J.H.Laity

Key ref:

Z.Wang et al. (2006). Solution structure of a Zap1 zinc-responsive domain provides insights into metalloregulatory transcriptional repression in Saccharomyces cerevisiae. J Mol Biol, 357, 1167-1183. PubMed id: 16483601 DOI: 10.1016/j.jmb.2006.01.010

Date:

03-Jun-05 Release date: 10-Jan-06

Protein chain

P47043  (ZAP1_YEAST) -  Zinc-responsive transcriptional regulator ZAP1 from Saccharomyces cerevisiae (strain ATCC 204508 / S288c)

Seq: 880 a.a.

Struc: 64 a.a.*

* PDB and UniProt seqs differ at 3 residue positions (black crosses)

DOI no: 10.1016/j.jmb.2006.01.010

J Mol Biol 357:1167-1183 (2006)

PubMed id: 16483601

Solution structure of a Zap1 zinc-responsive domain provides insights into metalloregulatory transcriptional repression in Saccharomyces cerevisiae.

Z.Wang, L.S.Feng, V.Matskevich, K.Venkataraman, P.Parasuram, J.H.Laity.

ABSTRACT

The Zap1 transcription factor controls expression of genes that regulate zinc homeostasis in Saccharomyces cerevisiae. The solution structure of two zinc fingers (zf1-2(CA3)) derived from a zinc-responsive domain of Zap1 (zf1-2) has been determined. Under zinc-limiting conditions, zinc finger 2 (zf2) from this domain has been shown to be a constitutive transcriptional activator. Moreover, repression of zf2 function in zinc-replete cells required zinc coordination to both canonical finger 1 (zf1) and zf2 metal sites, suggesting zf1-zf2 cooperativity underlies Zap1 metalloregulation. A structural basis for this cooperativity is identified here. Favorable inter-helical contacts in zf1-2(CA3) extend the individual finger hydrophobic cores through the zf1-zf2 interface. Tryptophan residues at position 5 in each finger provide numerous non-helical inter-finger contacts reminiscent of those observed in GLI1 zinc fingers 1 and 2. The molecular mechanism for zf1-dependent repression of zf2 transcriptional activation is explored further using NMR and CD titration studies. While zf1 independently forms a betabetaalpha solution structure, the majority of zf2 ensemble solution states do not adopt the canonical betabetaalpha zinc finger fold without zf1-zf2 interactions. Cooperative effects on Zn(II) affinities stemming from these finger-finger interactions are observed also in calorimetric studies, in which the 160(+/-20)nM (zf1) and 250(+/-40)nM (zf2) K(d) values for each individual finger increased substantially in the context of the zf1-2 protein (apparent K(dzf1-2WT)=4.6(+/-1.2)nM). On the basis of the above observations, we propose a mechanism for Zap1 transcriptional regulation in which zf1-zf2 interactions stabilize the betabetaalpha folded "repressed state" of the zf2 activation domain in the presence of cellular Zn(II) excess. Moreover, in contrast to earlier reports of <<1 labile zinc ion/Escherichia coli cell, the zf1-zf2 zinc affinities determined calorimetrically are consistent with Zn(II) levels >>1 labile zinc ion/eukaryotic cell.

Selected figure(s)

Figure 4.
Figure 4. Stereo image of the 20 lowest energy zf1-2[CA3] backbone structures (PDB entry 1ZW8). Zf1 and zf2 are colored wheat and slate, respectively, while the linker region is shaded gray.

Figure 10.
Figure 10. Cartoon representation of the two zinc fingers from (a) MBP-1^41 (mf1-2), and (b) GLI^33 (gf1-2). (a) The more extended arrangement of mf1-2 (structure 1 from PDB entry 1BBO), in which side-chain interactions forming the finger 1–2 interface involving residues from finger 1 (red), finger 2 (green), and the linker (gray) are indicated and annotated. In (b), amino acid side-chains from finger 1 (red), finger 2 (green), and the linker (gray) that appear to stabilize the gf1-2 two-finger structure (PDB entry 2GLI) are shown. Although portrayed here as an isolated two-finger domain for clarity, the X-ray structure from which the gf1-2 cartoon structure was derived consisted of Co(II)-bound GLI fingers 1–5 in complex with DNA (metal ligands are not included in the PDB entry). In the GLI-DNA structure, only fingers 2–5 made contact with the DNA.

The above figures are reprinted by permission from Elsevier: J Mol Biol (2006, 357, 1167-1183) copyright 2006.

Figures were selected by an automated process.