title: Determinants of Curvature-Sensing Behavior for MARCKS-Fragment Peptides.
abstract: It is increasingly recognized that membrane curvature plays an important role in various cellular activities such as signaling and trafficking, as well as key issues involving health and disease development. Thus, curvature-sensing peptides are essential to the study and detection of highly curved bilayer structures. The effector domain of myristoylated alanine-rich C-kinase substrate (MARCKS-ED) has been demonstrated to have curvature-sensing ability. Research of the MARCKS-ED has further revealed that its Lys and Phe residues play an essential role in how MARCKS-ED detects and binds to curved bilayers. MARCKS-ED has the added property of being a lower-molecular-weight curvature sensor, which offers advantages in production. With that in mind, this work investigates peptide-sequence-related factors that influence curvature sensing and explores whether peptide fragments of even shorter length can function as curvature sensors. Using both experimental and computational methods, we studied the curvature-sensing capabilities of seven fragments of MARCKS-ED. Two of the longer fragments were designed from approximately the two halves of the full-length peptide whereas the five shorter fragments were taken from the central stretch of MARCKS-ED. Fully atomistic molecular dynamics simulations show that the fragments that remain bound to the bilayer exhibit interactions with the bilayer similar to that of the full-length MARCKS-ED peptide. Fluorescence enhancement and anisotropy assays, meanwhile, reveal that five of the MARCKS fragments possess the ability to sense membrane curvature. Based on the sequences of the curvature-sensing fragments, it appears that the ability to sense curvature involves a balance between the numbers of positively charged residues and hydrophobic anchoring residues. Together, these findings help crystallize our understanding of the molecular mechanisms underpinning the curvature-sensing behaviors of peptides, which will prove useful in the design of future curvature sensors.
authors.affiliation: Department of Chemistry and Biochemistry, University of Colorado, Boulder, Colorado; BioFrontiers Institute, University of Colorado, Boulder, Colorado.
authors.forename: Armando J
authors.initials: AJ
authors.lastname: de Jesus
authors.affiliation: Department of Chemistry and Biochemistry, University of Colorado, Boulder, Colorado; BioFrontiers Institute, University of Colorado, Boulder, Colorado.
authors.forename: Ormacinda R
authors.initials: OR
authors.lastname: White
authors.affiliation: Department of Molecular, Cellular and Developmental Biology, University of Colorado, Boulder, Colorado; BioFrontiers Institute, University of Colorado, Boulder, Colorado.
authors.forename: Aaron D
authors.initials: AD
authors.lastname: Flynn
authors.affiliation: Department of Chemistry and Biochemistry, University of Colorado, Boulder, Colorado; BioFrontiers Institute, University of Colorado, Boulder, Colorado. Electronic address: hubert.yin@colorado.edu.
authors.forename: Hang
authors.initials: H
authors.lastname: Yin
mesh_terms: D000595:Amino Acid Sequence; D047908:Intracellular Signaling Peptides and Proteins / Q000737:chemistry*; D008051:Lipid Bilayers / Q000737:chemistry / Q000378:metabolism; D008239:Lysine / Q000737:chemistry; D008565:Membrane Proteins / Q000737:chemistry*; D056004:Molecular Dynamics Simulation; D000076250:Myristoylated Alanine-Rich C Kinase Substrate; D010446:Peptide Fragments / Q000737:chemistry* / Q000378:metabolism; D011487:Protein Conformation
chemical_list: D047908:Intracellular Signaling Peptides and Proteins; D008051:Lipid Bilayers; D008565:Membrane Proteins; D010446:Peptide Fragments; D000076250:Myristoylated Alanine-Rich C Kinase Substrate; D008239:Lysine