Dataset Information

Designed multi-stranded heme binding ?-sheet peptides in membrane.

ABSTRACT: Designed peptides demonstrating well-defined structures and functioning in membrane environment are of significant interest in developing novel proteins for membrane active biological processes including enzymes, electron transfer, ion channels and energy conversion. Heme proteins' ability to carry out multiple functions in nature has inspired the design of several helical heme binding peptides and proteins soluble in water and also recently in membrane. Naturally occurring ?-sheet proteins are both water and membrane soluble, and are known to bind heme, however, designed heme binding ?-sheet proteins are yet to be reported, plausibly because of the complex folding and difficulty in introducing heme binding sites in the ?-sheet structures. Here, we describe the design, NMR structures and biochemical functional characterization of four stranded and six stranded membrane soluble ?-sheet peptides that bind heme and di-heme, respectively. The designed peptides contain either DP-G or DP-DA residues for the nucleation of ?-turns intended to stabilize multi-stranded ?-sheet topologies and ligate heme with bis-His coordination between adjacent antiparallel ?-strands. Furthermore, we have optimized a high affinity heme binding pocket, Kd ? nM range, in the adjacent ?-strands by utilizing a series of four stranded ?-sheet peptides employing ?- and ?-amino acids. We find that there is a progressive increase in cofactor binding affinity in the designed peptides with the alkyl chain length of ?-amino acids. Notably, the six stranded ?-sheet peptide binds two molecules of heme in a cooperative fashion. The designed peptides perform peroxidase activity with varying ability and efficiently carried out electron transfer with membrane associated protein cytochrome c. The current study demonstrates the designing of functional ?-sheet proteins in a membrane environment and expands the repertoire of heme protein design.

SUBMITTER: D'Souza A

PROVIDER: S-EPMC5477022 | biostudies-literature | 2016 Apr

REPOSITORIES: biostudies-literature

ACCESS DATA

Publications

Designed multi-stranded heme binding β-sheet peptides in membrane.

D'Souza Areetha A Mahajan Mukesh M Bhattacharjya Surajit S

Chemical science 20160401 4

Designed peptides demonstrating well-defined structures and functioning in membrane environment are of significant interest in developing novel proteins for membrane active biological processes including enzymes, electron transfer, ion channels and energy conversion. Heme proteins' ability to carry out multiple functions in nature has inspired the design of several helical heme binding peptides and proteins soluble in water and also recently in membrane. Naturally occurring β-sheet proteins are ...[more]

PMID: 28660027

Similar Datasets

Project description:Over the past two decades, designed metallopeptides have held the promise for understanding a variety of fundamental questions in metallobiochemistry; however, these dreams have not yet been realized because of a lack of structural data to elaborate the protein scaffolds before metal complexation and the resultant metalated structures which ultimately exist. This is because there are few reports of structural characterization of such systems either in their metalated or nonmetalated forms and no examples where an apo structure and the corresponding metalated peptide assembly have both been defined by X-ray crystallography. Herein we present X-ray structures of two de novo designed parallel three-stranded coiled coils (designed using the heptad repeat (a → g)) CSL9C (CS = Coil Ser) and CSL19C in their nonmetalated forms, determined to 1.36 and 2.15 A resolutions, respectively. Leucines from either position 9 (a site) or 19 (d site) are replaced by cysteine to generate the constructs CSL9C and CSL19C, respectively, yielding thiol-rich pockets at the hydrophobic interior of these peptides, suitable to bind heavy metals such as As(III), Hg(II), Cd(II), and Pb(II). We use these structures to understand the inherent structural differences between a and d sites to clarify the basis of the observed differential spectroscopic behavior of metal binding in these types of peptides. Cys side chains of (CSL9C)(3) show alternate conformations and are partially preorganized for metal binding, whereas cysteines in (CSL19C)(3) are present as a single conformer. Zn(II) ions, which do not coordinate or influence Cys residues at the designed metal sites but are essential for forming X-ray quality crystals, are bound to His and Glu residues at the crystal packing interfaces of both structures. These "apo" structures are used to clarify the changes in metal site organization between metalated As(CSL9C)(3) and to speculate on the differential basis of Hg(II) binding in a versus d peptides. Thus, for the first time, one can establish general rules for heavy metal binding to Cys-rich sites in designed proteins which may provide insight for understanding how heavy metals bind to metallochaperones or metalloregulatory proteins.

Dataset Information

Designed multi-stranded heme binding ?-sheet peptides in membrane.

Publications

Designed multi-stranded heme binding β-sheet peptides in membrane.

Similar Datasets

OmicsDI is part of the ELIXIR infrastructure

Tweets