Answer to the Comments on G. Weber's "van't Hoff Revisited: Enthalpy of Association of Protein Subunits" by A. Holtzer and by R. Ragone, G. Colonna, and L. Ambrosone

1995 ◽  
Vol 99 (34) ◽  
pp. 13051-13051 ◽  
Author(s):  
Gregorio Weber
Keyword(s):  
Protein Subunits ◽  
Enthalpy Of Association

scholarly journals Nitrogenase MoFe protein subunits from Klebsiella pneumoniae expressed in foreign hosts. Characteristics and interactions.

1987 ◽  
Vol 262 (18) ◽  
pp. 8814-8820 ◽  
Author(s):  
D Holland ◽  
A Zilberstein ◽  
D Govezensky ◽  
D Salomon ◽  
A Zamir
Keyword(s):  
Klebsiella Pneumoniae ◽  
Protein Subunits ◽  
Mofe Protein

Substrate channels revealed in the trimericLactobacillus reuteribacterial microcompartment shell protein PduB

2012 ◽  
Vol 68 (12) ◽  
pp. 1642-1652 ◽  
Author(s):  
Allan Pang ◽  
Mingzhi Liang ◽  
Michael B. Prentice ◽  
Richard W. Pickersgill
Keyword(s):  
Tandem Repeats ◽  
Lactobacillus Reuteri ◽  
Protein Complexes ◽  
Protein Subunits ◽  
Shell Protein ◽  
Domain Structures ◽  
Bacterial Microcompartment ◽  
Major Shell ◽  
Carbon Molecules ◽  
Trimeric Structure

Lactobacillus reuterimetabolizes two similar three-carbon molecules, 1,2-propanediol and glycerol, within closed polyhedral subcellular bacterial organelles called bacterial microcompartments (metabolosomes). The outer shell of the propanediol-utilization (Pdu) metabolosome is composed of hundreds of mainly hexagonal protein complexes made from six types of protein subunits that share similar domain structures. The structure of the bacterial microcompartment protein PduB has a tandem structural repeat within the subunit and assembles into a trimer with pseudo-hexagonal symmetry. This trimeric structure forms sheets in the crystal lattice and is able to fit within a polymeric sheet of the major shell component PduA to assemble a facet of the polyhedron. There are three pores within the trimer and these are formed between the tandem repeats within the subunits. The structure shows that each of these pores contains three glycerol molecules that interact with conserved residues, strongly suggesting that these subunit pores channel glycerol substrate into the metabolosome. In addition to the observation of glycerol occupying the subunit channels, the presence of glycerol on the molecular threefold symmetry axis suggests a role in locking closed the central region.

Three-dimensional reconstruction of the stacked-disk aggregate of tobacco mosaic virus protein from electron micrographs

1971 ◽  
Vol 261 (837) ◽  
pp. 211-219 ◽  
Keyword(s):  
Electron Microscope ◽  
Tobacco Mosaic Virus ◽  
Mosaic Virus ◽  
Three Dimensional ◽  
Dimensional Structure ◽  
Virus Protein ◽  
Protein Subunits ◽  
Microscope Images ◽  
Dimensional Reconstruction ◽  
Inner Parts

The three-dimensional structure of the stacked-disk rod of tobacco mosaic virus protein has been reconstructed to a resolution of about 2 nm from electron microscope images. Closed rings of seventeen protein subunits (compared with 16 ⅓ in one turn of the virus helix) are stacked in polar fashion, the stacking being accompanied by an axial perturbation of periodicity 5.3 nm connecting successive pairs of rings into disks. The axial perturbation consists of a movement towards each other of the outer parts of the subunits in the two rings comprising a disk, together with a movement of the inner parts in the opposite direction. This could be explained either by a bending of parts of the subunits in the appropriate directions or by a bodily tilting of the subunits in the two rings in opposite directions.

scholarly journals Comprehensive Epitope Analysis of Human Immunodeficiency Virus Type 1 (HIV-1)-Specific T-Cell Responses Directed against the Entire Expressed HIV-1 Genome Demonstrate Broadly Directed Responses, but No Correlation to Viral Load

2003 ◽  
Vol 77 (3) ◽  
pp. 2081-2092 ◽  
Author(s):  
M. M. Addo ◽  
X. G. Yu ◽  
A. Rathod ◽  
D. Cohen ◽  
R. L. Eldridge ◽  
...  
Keyword(s):  
T Cell ◽  
T Cell Responses ◽  
Protein Subunits ◽  
Cell Responses ◽  
Cellular Immune Responses ◽  
Immunodeficiency Virus ◽  
Total Magnitude ◽  
Cellular Immune ◽  
Hiv 1

ABSTRACT Cellular immune responses play a critical role in the control of human immunodeficiency virus type 1 (HIV-1); however, the breadth of these responses at the single-epitope level has not been comprehensively assessed. We therefore screened peripheral blood mononuclear cells (PBMC) from 57 individuals at different stages of HIV-1 infection for virus-specific T-cell responses using a matrix of 504 overlapping peptides spanning all expressed HIV-1 proteins in a gamma interferon-enzyme-linked immunospot (Elispot) assay. HIV-1-specific T-cell responses were detectable in all study subjects, with a median of 14 individual epitopic regions targeted per person (range, 2 to 42), and all 14 HIV-1 protein subunits were recognized. HIV-1 p24-Gag and Nef contained the highest epitope density and were also the most frequently recognized HIV-1 proteins. The total magnitude of the HIV-1-specific response ranged from 280 to 25,860 spot-forming cells (SFC)/106 PBMC (median, 4,245) among all study participants. However, the number of epitopic regions targeted, the protein subunits recognized, and the total magnitude of HIV-1-specific responses varied significantly among the tested individuals, with the strongest and broadest responses detectable in individuals with untreated chronic HIV-1 infection. Neither the breadth nor the magnitude of the total HIV-1-specific CD8+-T-cell responses correlated with plasma viral load. We conclude that a peptide matrix-based Elispot assay allows for rapid, sensitive, specific, and efficient assessment of cellular immune responses directed against the entire expressed HIV-1 genome. These data also suggest that the impact of T-cell responses on control of viral replication cannot be explained by the mere quantification of the magnitude and breadth of the CD8+-T-cell response, even if a comprehensive pan-genome screening approach is applied.

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