scholarly journals Improving prediction of helix-helix packing in membrane proteins using predicted contact numbers as restraints

2017 ◽  
Vol 85 (7) ◽  
pp. 1212-1221 ◽  
Author(s):  
Bian Li ◽  
Jeffrey Mendenhall ◽  
Elizabeth Dong Nguyen ◽  
Brian E. Weiner ◽  
Axel W. Fischer ◽  
...  
Keyword(s):  
Membrane Proteins ◽  
Helix Packing

scholarly journals Helix-packing motifs in membrane proteins

2006 ◽  
Vol 103 (37) ◽  
pp. 13658-13663 ◽  
Author(s):  
R. F. S. Walters ◽  
W. F. DeGrado
Keyword(s):  
Membrane Proteins ◽  
Helix Packing

scholarly journals Helix Packing in Polytopic Membrane Proteins: Role of Glycine in Transmembrane Helix Association

1999 ◽  
Vol 77 (3) ◽  
pp. 1609-1618 ◽  
Author(s):  
Maryam M. Javadpour ◽  
Markus Eilers ◽  
Michel Groesbeek ◽  
Steven O. Smith
Keyword(s):  
Membrane Proteins ◽  
Transmembrane Helix ◽  
Helix Packing

Helix packing in membrane proteins

1997 ◽  
Vol 272 (5) ◽  
pp. 780-789 ◽  
Author(s):  
James U Bowie
Keyword(s):  
Membrane Proteins ◽  
Helix Packing

scholarly journals Small-residue packing motifs modulate the structure and function of a minimal de novo membrane protein

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Paul Curnow ◽  
Benjamin J. Hardy ◽  
Virginie Dufour ◽  
Christopher J. Arthur ◽  
Richard Stenner ◽  
...  
Keyword(s):  
Membrane Proteins ◽  
Membrane Protein ◽  
Transmembrane Domain ◽  
De Novo ◽  
Zinc Protoporphyrin ◽  
Sequence Motifs ◽  
Conserved Sequence ◽  
Starting Point ◽  
Helix Packing ◽  
The Impact

Abstract Alpha-helical integral membrane proteins contain conserved sequence motifs that are known to be important in helix packing. These motifs are a promising starting point for the construction of artificial proteins, but their potential has not yet been fully explored. Here, we study the impact of introducing a common natural helix packing motif to the transmembrane domain of a genetically-encoded and structurally dynamic de novo membrane protein. The resulting construct is an artificial four-helix bundle with lipophilic regions that are defined only by the amino acids L, G, S, A and W. This minimal proto-protein could be recombinantly expressed by diverse prokaryotic and eukaryotic hosts and was found to co-sediment with cellular membranes. The protein could be extracted and purified in surfactant micelles and was monodisperse and stable in vitro, with sufficient structural definition to support the rapid binding of a heme cofactor. The reduction in conformational diversity imposed by this design also enhances the nascent peroxidase activity of the protein-heme complex. Unexpectedly, strains of Escherichia coli expressing this artificial protein specifically accumulated zinc protoporphyrin IX, a rare cofactor that is not used by natural metalloenzymes. Our results demonstrate that simple sequence motifs can rigidify elementary membrane proteins, and that orthogonal artificial membrane proteins can influence the cofactor repertoire of a living cell. These findings have implications for rational protein design and synthetic biology.

Changes Occur in Plasma Membrane Turnover when K562 Leukemia Cells are Induced to Differentiate

1982 ◽  
Vol 40 ◽  
pp. 286-287
Author(s):  
L. M. Marshall
Keyword(s):  
Plasma Membrane ◽  
Membrane Proteins ◽  
Intracellular Transport ◽  
Parent Cell ◽  
Membrane Turnover ◽  
Coated Pits ◽  
Surface Distribution ◽  
Specific Proteins ◽  
Erythroleukemic Cell ◽  
Specific Membrane

A human erythroleukemic cell line, metabolically blocked in a late stage of erythropoiesis, becomes capable of differentiation along the normal pathway when grown in the presence of hemin. This process is characterized by hemoglobin synthesis followed by rearrangement of the plasma membrane proteins and culminates in asymmetrical cytokinesis in the absence of nuclear division. A reticulocyte-like cell buds from the nucleus-containing parent cell after erythrocyte specific membrane proteins have been sequestered into its membrane. In this process the parent cell faces two obstacles. First, to organize its erythrocyte specific proteins at one pole of the cell for inclusion in the reticulocyte; second, to reduce or abolish membrane protein turnover since hemoglobin is virtually the only protein being synthesized at this stage. A means of achieving redistribution and cessation of turnover could involve movement of membrane proteins by a directional lipid flow. Generation of a lipid flow towards one pole and accumulation of erythrocyte-specific membrane proteins could be achieved by clathrin coated pits which are implicated in membrane endocytosis, intracellular transport and turnover. In non-differentiating cells, membrane proteins are turned over and are random in surface distribution. If, however, the erythrocyte specific proteins in differentiating cells were excluded from endocytosing coated pits, not only would their turnover cease, but they would also tend to drift towards and collect at the site of endocytosis. This hypothesis requires that different protein species are endocytosed by the coated vesicles in non-differentiating than by differentiating cells.

Image Analysis of Intramembrane Particles in Freeze-Fractured Biomembranes Using Computer Simulation Techniques

1975 ◽  
Vol 33 ◽  
pp. 214-215
Author(s):  
D.J. Benefiel ◽  
R.S. Weinstein
Keyword(s):  
Membrane Proteins ◽  
Freeze Fracture ◽  
Integral Membrane Proteins ◽  
Systematic Evaluation ◽  
Intramembrane Particles ◽  
Modeling Methods ◽  
Simulation Techniques ◽  
Freeze Fracture Electron Microscopy ◽  
Fracture Electron ◽  
Computer Simulation Techniques

Intramembrane particles (IMP or MAP) are components of most biomembranes. They are visualized by freeze-fracture electron microscopy, and they probably represent replicas of integral membrane proteins. The presence of MAP in biomembranes has been extensively investigated but their detailed ultrastructure has been largely ignored. In this study, we have attempted to lay groundwork for a systematic evaluation of MAP ultrastructure. Using mathematical modeling methods, we have simulated the electron optical appearances of idealized globular proteins as they might be expected to appear in replicas under defined conditions. By comparing these images with the apearances of MAPs in replicas, we have attempted to evaluate dimensional and shape distortions that may be introduced by the freeze-fracture technique and further to deduce the actual shapes of integral membrane proteins from their freezefracture images.

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