The Interpretation of Infrared Dichroism in Fibrous Protein Structures

1953 ◽  
Vol 21 (9) ◽  
pp. 1511-1515 ◽  
Author(s):  
R. D. B. Fraser
Keyword(s):  
Protein Structures ◽  
Fibrous Protein ◽  
Infrared Dichroism

Phosphates and other enzymes considered in relation to active transport and the function of fibrous protein structures

1954 ◽  
Vol 142 (907) ◽  
pp. 146-154 ◽  
Keyword(s):  
Protein Structures ◽  
Enzymic Activity ◽  
Critical Examination ◽  
Phosphate Ester ◽  
Normal Position ◽  
Tissue Sections ◽  
Phosphate Ion ◽  
Fibrous Protein ◽  
Active Transfer ◽  
Sufficient Precision

Many students of active transfer of molecules through membranes have postulated that the transfer is mediated with the aid of enzymes, particularly phosphatases. Verzar and Wilbrandt and Lastz in particular emphasized this point. However, all theories of this nature imply that certain enzyme systems are localized in particular regions of cells. Until quite recently it was not possible to determine the site of enzymes with sufficient precision to permit experimental investigation of the postulated localizations. The first experiments on the localization of alkaline phosphatase were carried out by Robison (1923). In these experiments tissue sections were exposed to a solution containing a phosphate ester and calcium. Where phosphatase was present phosphate ion was liberated from ester by enzymic hydrolysis, and precipitated in the section as calcium phosphate. Gomori (1939) and Takamatsu (1939) showed that the precipitate so formed was deposited in certain cellular sites only, and claimed that these sites were the actual sites of enzymic activity. Subsequent investigations have shown that this claim is, in part, justified. Before such claims can be accepted critical examination of techniques is essential. Answers must be provided to the following questions: ( а ) How much enzyme is destroyed during the preparation of tissue sections, and if there is destruction, does it occur unequally at different sites? ( b ) Is the precipitate formed at the actual site of enzymic activity, or is it formed at sites having a special affinity for the precipitate? ( c ) Is the enzyme in a tissue section in its physiologically normal position? ( d ) Is the substrate for the enzyme able to penetrate to all sites of enzyme activity?

Calculated dynamical scattering in a fibrous protein structure

1992 ◽  
Vol 50 (2) ◽  
pp. 1176-1177
Author(s):  
P.W. Dyson ◽  
A.E.C. Spargo ◽  
P.A. Tulloch ◽  
A.W.S. Johnson
Keyword(s):  
Fourier Transforms ◽  
Imaging Techniques ◽  
Protein Structures ◽  
X Ray Diffraction ◽  
Data Set ◽  
Praying Mantis ◽  
Ordered Arrays ◽  
Fibrous Protein ◽  
Dose Imaging ◽  
Made In

Despite many technical, experimental and in principle difficulties, particularly in regard to radiation damage and stability of the structure at the atomic level, considerable progress has been made in the application of the combined electron microscopy/electron diffraction (EM/ED) technique to the solution of protein structures. The technique now represents a possible alternative to x-ray diffraction for those cases where the protein is difficult or impossible to grow as macrocrystals, provided that the molecule can be incorporated in microcrystals or two-dimensional ordered arrays. Encouraged by this we have recently recorded images and diffraction intensities from microcrystals of an alpha-helical coiledcoil protein extracted from the ootheca of the praying mantis. The ED data shows reflections out to beyond 2Å, though not uniformly in all directions. Fourier transforms of the corresponding digitised images show resolution out to nearly 3Å and this data is being used to phase the ED data. All data was recorded from frozen-hydrated specimens at 400kV in a super-fluid helium specimen stage of a JEM 4000EX electron microscope using spot-scan and low-dose imaging techniques. Further work aimed at collecting a 3-d data set to a resolution of 3Å using tilted crystals is continuing.

scholarly journals Injectable collagen in correction of age-related skin changes: experimental and clinical parallels

2019 ◽  
pp. 71-77 ◽  
Author(s):  
NE Manturova ◽  
AG Stenko ◽  
YaA Petinati ◽  
EA Chaikovskaya ◽  
AA Bolgarina
Keyword(s):  
Protein Structures ◽  
Laboratory Animals ◽  
Facial Skin ◽  
Serious Adverse Events ◽  
Skin Changes ◽  
Clinical Scales ◽  
Fibrous Protein ◽  
Age Related ◽  
Indirect Indication

To a large extent, age-related facial skin changes, wrinkles and flabbiness, are attributed to the structural alterations in dermis, including of collagen fibers fragmentation and disorganization. There are various cosmetological correction methods that aim to activate neocollagenesis and dermal remodeling. From this perspective, intradermal injections of exogenous collagen preparations seem logical. This study aimed to investigate the efficacy and safety of Collost 7% collagen complex applied to correct the age-related facial skin changes, as well as clarify the possible mechanisms of skin rejuvenation resulting from a course of intradermal injections. 35 participants entered the study, 30 of them finished it. A set of indicators describing age-related skin changes was assessed with the help of clinical scales; the assessment revealed a pronounced improvement in the quality of the patients' skin, including smoothed relief in the area of localization of fine wrinkles. The therapy resulted in a statistically significant improvement of the skin's elasticity, which, combined with the changes discovered through US scanning (greater dermis thickness and echodensity), is an indirect indication of skin restructuring associated with accumulation of fibrous protein structures. These results allow parallels with the experimental data that shows activation of neocollagenesis in the skin of laboratory animals after a course of Collost 7% gel. The research revealed no serious adverse events. A course of collagen administered intradermally can be recommended as an aesthetic correction procedure, as well as means of prevention of atrophy that has a significant effect on skin's appearance and health status.

Relationships between hierarchical structure and properties in macromolecular systems

1987 ◽  
Vol 45 ◽  
pp. 440-443
Author(s):  
E. Baer
Keyword(s):  
Uniaxial Tension ◽  
Hierarchical Structure ◽  
Inorganic Material ◽  
Hierarchical Structures ◽  
Bone Collagen ◽  
Structure And Properties ◽  
Connective Tissues ◽  
Scale Level ◽  
Fibrous Protein ◽  
Macromolecular Systems

The most advanced macromolecular materials are found in plants and animals, and certainly the connective tissues in mammals are amongst the most advanced macromolecular composites known to mankind. The efficient use of collagen, a fibrous protein, in the design of both soft and hard connective tissues is worthy of comment. Very crudely, in bone collagen serves as a highly efficient binder for the inorganic hydroxyappatite which stiffens the structure. The interactions between the organic fiber of collagen and the inorganic material seem to occur at the nano (scale) level of organization. Epitatic crystallization of the inorganic phase on the fibers has been reported to give a highly anisotropic, stress responsive, structure. Soft connective tissues also have sophisticated oriented hierarchical structures. The collagen fibers are “glued” together by a highly hydrated gel-like proteoglycan matrix. One of the simplest structures of this type is tendon which functions primarily in uniaxial tension as a reinforced elastomeric cable between muscle and bone.

The microtubule associated protein (MAP) tau forms a new class of triple-stranded left-hand helical fibrous protein polymer

1992 ◽  
Vol 50 (1) ◽  
pp. 540-541
Author(s):  
G. C. Ruben ◽  
K. Iqbal ◽  
I. Grundke-Iqbal ◽  
H. Wisniewski ◽  
T. L. Ciardelli ◽  
...  
Keyword(s):  
Axial Ratio ◽  
Normal Structure ◽  
Paired Helical Filaments ◽  
Left Hand ◽  
New Class ◽  
Protein Polymer ◽  
Fibrous Protein ◽  
Protein Map ◽  
Neurotransmitter Transport ◽  
Alzheimer Neurofibrillary Tangles

In neurons, the microtubule associated protein, tau, is found in the axons. Tau stabilizes the microtubules required for neurotransmitter transport to the axonal terminal. Since tau has been found in both Alzheimer neurofibrillary tangles (NFT) and in paired helical filaments (PHF), the study of tau's normal structure had to preceed TEM studies of NFT and PHF. The structure of tau was first studied by ultracentrifugation. This work suggested that it was a rod shaped molecule with an axial ratio of 20:1. More recently, paraciystals of phosphorylated and nonphosphoiylated tau have been reported. Phosphorylated tau was 90-95 nm in length and 3-6 nm in diameter where as nonphosphorylated tau was 69-75 nm in length. A shorter length of 30 nm was reported for undamaged tau indicating that it is an extremely flexible molecule. Tau was also studied in relation to microtubules, and its length was found to be 56.1±14.1 nm.

Insights into the biochemical and functional characterization of sortase E transpeptidase of Corynebacterium glutamicum

2019 ◽  
Vol 476 (24) ◽  
pp. 3835-3847 ◽  
Author(s):  
Aliyath Susmitha ◽  
Kesavan Madhavan Nampoothiri ◽  
Harsha Bajaj
Keyword(s):  
Protein Engineering ◽  
Cell Attachment ◽  
Functional Characterization ◽  
Protein Structures ◽  
Structural Similarity ◽  
Surface Proteins ◽  
Sortase A ◽  
Peptide Cleavage ◽  
New Findings

Most Gram-positive bacteria contain a membrane-bound transpeptidase known as sortase which covalently incorporates the surface proteins on to the cell wall. The sortase-displayed protein structures are involved in cell attachment, nutrient uptake and aerial hyphae formation. Among the six classes of sortase (A–F), sortase A of S. aureus is the well-characterized housekeeping enzyme considered as an ideal drug target and a valuable biochemical reagent for protein engineering. Similar to SrtA, class E sortase in GC rich bacteria plays a housekeeping role which is not studied extensively. However, C. glutamicum ATCC 13032, an industrially important organism known for amino acid production, carries a single putative sortase (NCgl2838) gene but neither in vitro peptide cleavage activity nor biochemical characterizations have been investigated. Here, we identified that the gene is having a sortase activity and analyzed its structural similarity with Cd-SrtF. The purified enzyme showed a greater affinity toward LAXTG substrate with a calculated KM of 12 ± 1 µM, one of the highest affinities reported for this class of enzyme. Moreover, site-directed mutation studies were carried to ascertain the structure functional relationship of Cg-SrtE and all these are new findings which will enable us to perceive exciting protein engineering applications with this class of enzyme from a non-pathogenic microbe.

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