scholarly journals The quaternary structure in solution of human complement subcomponent C1r2C1s2

1989 ◽  
Vol 263 (2) ◽  
pp. 463-469 ◽  
Author(s):  
S J Perkins ◽  
A S Nealis
Keyword(s):  
Neutron Scattering ◽  
Quaternary Structure ◽  
Serine Proteinase ◽  
Linear Structure ◽  
Linear Arrangement ◽  
Good Account ◽  
Short Consensus Repeat ◽  
20 Nm ◽  
Structure In Solution ◽  
Domain Length

C1r2C1s2 is a subcomponent of first component C1 of the complement cascade. Previously two distinct models for its structure have been described, in which C1r2C1s2 is either a linear rod-like assembly of the globular domains found in each of C1s and C1r, or these domains are arranged to form an asymmetric X-shaped structure. These two models were evaluated by using hydrodynamic simulations and neutron scattering. The data on C1s, C1s2 and C1r are readily represented by straight hydrodynamic cylinders, but not C1r2 or C1r2C1s2. Tests of the X-structure for C1r2 and C1r2C1s2 successfully predicted the experimental sedimentation coefficients, thus supporting this model. Neutron scattering analyses on C1s and C1r2 are consistent with a linear structure for C1s, but not for C1r2. An X-shaped structure for C1r2 was found to give a good account of the neutron data at large scattering angles. The total length of the C1s and C1r monomers was determined as 17-20 nm, which is compatible with electron microscopy. On the basis of the known sequences of C1r and C1s, this length is accounted for by a linear arrangement of a serine-proteinase domain (length 4 nm), two short consensus repeat domains (2 x 4 nm), and a globular entity containing the I, II and III domains (4-7 nm).

scholarly journals Purification and characterization of a tetrameric α-macroglobulin proteinase inhibitor from the gastropod mollusc Biomphalaria glabrata

1996 ◽  
Vol 316 (3) ◽  
pp. 893-900 ◽  
Author(s):  
Randall C. BENDER ◽  
Christopher J. BAYNE
Keyword(s):  
Quaternary Structure ◽  
Proteinase Inhibitors ◽  
Cysteine Proteinase ◽  
Serine Proteinase ◽  
Biomphalaria Glabrata ◽  
Sedimentation Equilibrium ◽  
Flight Mass Spectrometry ◽  
Isolation And Characterization ◽  
Α2 Macroglobulin

The α-macroglobulin proteinase inhibitors (αMs) are a family of proteins with the unique ability to inhibit a broad spectrum of proteinases. Whereas monomeric, dimeric and tetrameric αMs have been identified in vertebrates, all invertebrate αMs characterized so far have been dimeric. This paper reports the isolation and characterization of a tetrameric αM from the tropical planorbid snail Biomphalaria glabrata. The sequence of 18 amino acids at the N-terminus indicates homology with other αMs. The subunit mass of approx. 200 kDa was determined by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry and SDS/PAGE. The quaternary structure was determined by sedimentation equilibrium centrifugation and native pore-limit electrophoresis. Evidence for a thioester is provided by the fact that methylamine treatment prevents the autolytic cleavage of the snail αM subunit and results in the release of 4 mol of thiols per mol of snail αM. The snail αM inhibited the serine proteinase trypsin, the cysteine proteinase bromelain and the metalloproteinase thermolysin. The spectrum of proteinases inhibited, together with the demonstration of steric protection of the proteinase active site and a ‘slow to fast’ conformational change after reacting with trypsin, all suggest that the inhibitory mechanism of the snail αM is similar to the ‘trap mechanism’ of human α2-macroglobulin.

scholarly journals Modelling of the serine-proteinase fold by X-ray and neutron scattering and sedimentation analyses: occurrence of the fold in factor D of the complement system

1993 ◽  
Vol 295 (1) ◽  
pp. 87-99 ◽  
Author(s):  
S J Perkins ◽  
K F Smith ◽  
J M Kilpatrick ◽  
J E Volanakis ◽  
R B Sim
Keyword(s):  
Neutron Scattering ◽  
Sedimentation Coefficient ◽  
Serine Proteinase ◽  
Scattering Data ◽  
Multidomain Proteins ◽  
X Ray ◽  
Trypsinogen Activation ◽  
X Ray Scattering ◽  
Monomeric Proteins ◽  
Ray Scattering

Solution scattering is a powerful means of determining the overall arrangement of domains in the multidomain proteins of complement. the serine-proteinase domain is central to all proteolytic events during complement activation. As models of this domain, bovine beta-trypsin, trypsinogen, alpha-chymotrypsin and chymotrypsinogen A were studied by neutron and X-ray synchrotron solution scattering. At pH 7, all the X-ray and neutron M(r) values corresponded to monomeric proteins. The X-ray radii of gyration, RG, of beta-trypsin, trypsinogen, alpha-chymotrypsin and chymotrypsinogen A (measured in positive solute-solvent contrasts) were 1.59 nm, 1.78 nm, 1.71 nm and 1.76 nm (+/- 0.05-0.11 nm) in that order. Neutron contrast variation showed that the RG at infinite contrast, RC, for these four proteins were 1.57 nm, 1.70 nm, 1.67 nm and 1.78 nm (+/- 0.03 nm) in that same order. The radial inhomogeneity of neutron-scattering density, alpha, was positive at (5-13) x 10(-5), and corresponds to the preponderance of hydrophilic residues near the protein surface. On trypsinogen activation, a small reduction in the RG value of 0.13 +/- 0.07 nm was just detectable, while the RG of chymotrypsinogen A was unchanged after activation. The RC and alpha values of the four proteins can be calculated by using crystallographic co-ordinates. The reduced RG of beta-trypsin relative to trypsinogen was explained in terms of the removal of the extended N-terminal hexapeptide of trypsinogen. The full X-ray and neutron-scattering curves in positive and negative contrasts agreed well with scattering curves calculated from crystallographic coordinates to a nominal structural resolution of 4.5 nm, provided that the internal structure was considered in neutron modelling, and that the hydration was considered in X-ray modelling. Sedimentation-coefficient data also provide information on the disposition of domains in multidomain proteins. It was found that the hydrated X-ray sphere model could be directly utilized to calculate sedimentation coefficients. X-ray scattering on factor D showed from its RG of 1.78 nm that this is monomeric and very similar in structure to beta-trypsin. The X-ray-scattering curve of factor D was readily modelled using the beta-trypsin crystal structure after allowance for sequence changes. The success of these modellings provides a basis for the constrained modelling of solution scattering data for the multidomain proteins of complement.

scholarly journals Small-angle neutron scattering reveals the assembly mode and oligomeric architecture of TET, a large, dodecameric aminopeptidase

2014 ◽  
Vol 70 (11) ◽  
pp. 2983-2993 ◽  
Author(s):  
Alexandre Appolaire ◽  
Eric Girard ◽  
Matteo Colombo ◽  
M. Asunción Durá ◽  
Martine Moulin ◽  
...  
Keyword(s):  
Neutron Scattering ◽  
Small Angle ◽  
Small Angle Neutron Scattering ◽  
Quaternary Structure ◽  
De Novo ◽  
Biological Systems ◽  
Catalytic Efficiency ◽  
Building Blocks ◽  
Assembly Pathways

The specific self-association of proteins into oligomeric complexes is a common phenomenon in biological systems to optimize and regulate their function. However,de novostructure determination of these important complexes is often very challenging for atomic-resolution techniques. Furthermore, in the case of homo-oligomeric complexes, or complexes with very similar building blocks, the respective positions of subunits and their assembly pathways are difficult to determine using many structural biology techniques. Here, an elegant and powerful approach based on small-angle neutron scattering is applied, in combination with deuterium labelling and contrast variation, to elucidate the oligomeric organization of the quaternary structure and the assembly pathways of 468 kDa, hetero-oligomeric and symmetricPyrococcus horikoshiiTET2–TET3 aminopeptidase complexes. The results reveal that the topology of thePhTET2 andPhTET3 dimeric building blocks within the complexes is not casual but rather suggests that their quaternary arrangement optimizes the catalytic efficiency towards peptide substrates. This approach bears important potential for the determination of quaternary structures and assembly pathways of large oligomeric and symmetric complexes in biological systems.

scholarly journals Alpha-catenin structure in solution and in complex with F-actin as revealed by small-angle X-ray and neutron scattering

2018 ◽  
Vol 74 (a1) ◽  
pp. a457-a457
Author(s):  
Iain D. Nicholl ◽  
Tsutomu Matsui ◽  
Thomas M. Weiss ◽  
Christopher B. Stanley ◽  
William T. Heller ◽  
...  
Keyword(s):  
Neutron Scattering ◽  
Small Angle ◽  
X Ray ◽  
Structure In Solution

scholarly journals The Influence of Talc Addition on the Performance of Polypropylene Membranes Formed by TIPS Method

Membranes ◽  
2019 ◽  
Vol 9 (5) ◽  
pp. 63 ◽  
Author(s):  
Marek Gryta
Keyword(s):  
Linear Structure ◽  
Membrane Distillation ◽  
Polymer Chains ◽  
Thermally Induced Phase Separation ◽  
Linear Arrangement ◽  
Thermally Induced ◽  
Capillary Membranes ◽  
The Stability ◽  
Long Term Studies

The effect of talc addition on the morphology of capillary membranes formed by a thermally induced phase separation (TIPS) method was investigated in the presented work. The usability of such formed membranes for membrane distillation was evaluated. Two types of commercial capillary polypropylene membranes, fabricated for microfiltration process, were applied in the studies. A linear arrangement of polymer chains was obtained in the walls of membranes formed without a talc addition. In the case of membranes blended with talc, the linear structure was disordered, and a more porous structure was obtained. The changes in morphology enhanced the mechanical properties of blended membranes, and their lower thermal degradation was observed during 350 h of membrane distillation studies. Long-term studies confirmed the stability of talc dispersion in the membrane matrix. A leaching of talc from polypropylene (PP) membranes was not found during the membrane distillation (MD) process.

Quaternary structure of Limulus polyphemus hemocyanin

1978 ◽  
Vol 36 (2) ◽  
pp. 176-177
Author(s):  
T. Wichertjes ◽  
E.J. Kwak ◽  
E.F.J. Van Bruggen
Keyword(s):  
Electron Microscopy ◽  
Functional Properties ◽  
Horseshoe Crab ◽  
Temperature Jump ◽  
Quaternary Structure ◽  
Crystallographic Analysis ◽  
Limulus Polyphemus ◽  
Oxygen Binding ◽  
X Ray ◽  
Intact Molecule

Hemocyanin of the horseshoe crab (Limulus polyphemus) has been studied in nany ways. Recently the structure, dissociation and reassembly was studied using electron microscopy of negatively stained specimens as the method of investigation. Crystallization of the protein proved to be possible and X-ray crystallographic analysis was started. Also fluorescence properties of the hemocyanin after dialysis against Tris-glycine buffer + 0.01 M EDTA pH 8.9 (so called “stripped” hemocyanin) and its fractions II and V were studied, as well as functional properties of the fractions by NMR. Finally the temperature-jump method was used for assaying the oxygen binding of the dissociating molecule and of preparations of isolated subunits. Nevertheless very little is known about the structure of the intact molecule. Schutter et al. suggested that the molecule possibly consists of two halves, combined in a staggered way, the halves themselves consisting of four subunits arranged in a square.

Sign in / Sign up

Export Citation Format

Share Document