PDBsum entry 1dn3

De novo protein

PDB id: 1dn3

Contents

Protein chain

15 a.a.

PDB id:

1dn3

Name:

De novo protein

Title:

Nmr structure of a model hydrophilic amphipathic helical basic peptide

Structure:

Human platelet factor 4, segment 59-73. Chain: a. Engineered: yes. Mutation: yes. Other_details: chemically synthesized

Source:

Synthetic: yes. Homo sapiens. Organism_taxid: 9606

NMR struc:

1 models

Authors:

R.Montserret,M.J.Mcleish,A.Bockmann,C.Geourjon,F.Penin

Key ref:

R.Montserret et al. (2000). Involvement of electrostatic interactions in the mechanism of peptide folding induced by sodium dodecyl sulfate binding. Biochemistry, 39, 8362-8373. PubMed id: 10913242 DOI: 10.1021/bi000208x

Date:

16-Dec-99 Release date: 12-Jan-00

Protein chain

P02776  (PLF4_HUMAN) -  Platelet factor 4 from Homo sapiens

Seq: 101 a.a.

Struc: 15 a.a.*

* PDB and UniProt seqs differ at 4 residue positions (black crosses)

Enzyme reactions

• Enzyme class: E.C.?

DOI no: 10.1021/bi000208x

Biochemistry 39:8362-8373 (2000)

PubMed id: 10913242

Involvement of electrostatic interactions in the mechanism of peptide folding induced by sodium dodecyl sulfate binding.

R.Montserret, M.J.McLeish, A.Böckmann, C.Geourjon, F.Penin.

ABSTRACT

Sodium dodecyl sulfate (SDS) has consistently been shown to induce secondary structure, particularly alpha-helices, in polypeptides, and is commonly used to model membrane and other hydrophobic environments. However, the precise mechanism by which SDS induces these conformational changes remains unclear. To examine the role of electrostatic interactions in this mechanism, we have designed two hydrophilic, charged amphipathic alpha-helical peptides, one basic (QAPAYKKAAKKLAES) and the other acidic (QAPAYEEAAEELAKS), and their structures were studied by CD and NMR. The design of the peptides is based on the sequence of the segment of residues 56-70 of human platelet factor 4 [PF4(56-70), QAPLYKKIIKKLLES]. Both peptides were unstructured in water, and in the presence of neutral, zwitterionic, or cationic detergents. However, in SDS at neutral pH, the basic peptide folded into an alpha-helix. By contrast, the pH needed to be lowered to 1.8 before alpha-helix formation was observed for the acidic peptide. Strong, attractive electrostatic interactions, between the anionic groups of SDS and the cationic groups of the lysines, appeared to be necessary to initiate the folding of the basic peptide. NMR analysis showed that the basic peptide was fully embedded in SDS-peptide micelles, and that its three-dimensional alpha-helical structure could be superimposed on that of the native structure of PF4(56-70). These results enabled us to propose a working model of the basic peptide-SDS complex, and a mechanism for SDS-induced alpha-helical folding. This study demonstrates that, while the folding of peptides is mostly driven by hydrophobic effects, electrostatic interactions play a significant role in the formation and the stabilization of SDS-induced structure.