The Experts below are selected from a list of 153 Experts worldwide ranked by ideXlab platform
Jiannjiu Wu - One of the best experts on this subject based on the ideXlab platform.
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evolutionary origins of c terminal gpp n 3 Hydroxyproline formation in vertebrate tendon collagen
PLOS ONE, 2014Co-Authors: David M Hudson, Maryann Weis, Jiannjiu Wu, Rachel Werther, David R EyreAbstract:Approximately half the proline residues in fibrillar collagen are hydroxylated. The predominant form is 4-Hydroxyproline, which helps fold and stabilize the triple helix. A minor form, 3-Hydroxyproline, still has no clear function. Using peptide mass spectrometry, we recently revealed several previously unknown molecular sites of 3-Hydroxyproline in fibrillar collagen chains. In fibril-forming A-clade collagen chains, four new partially occupied 3-Hydroxyproline sites were found (A2, A3, A4 and (GPP)n) in addition to the fully occupied A1 site at Pro986. The C-terminal (GPP)n motif has five consecutive GPP triplets in α1(I), four in α2(I) and three in α1(II), all subject to 3-hydroxylation. The evolutionary origins of this substrate sequence were investigated by surveying the pattern of its 3-Hydroxyproline occupancy from early chordates through amphibians, birds and mammals. Different tissue sources of type I collagen (tendon, bone and skin) and type II collagen (cartilage and notochord) were examined by mass spectrometry. The (GPP)n domain was found to be a major substrate for 3-hydroxylation only in vertebrate fibrillar collagens. In higher vertebrates (mouse, bovine and human), up to five 3-Hydroxyproline residues per (GPP)n motif were found in α1(I) and four in α2(I), with an average of two residues per chain. In vertebrate type I collagen the modification exhibited clear tissue specificity, with 3-Hydroxyproline prominent only in tendon. The occupancy also showed developmental changes in Achilles tendon, with increasing 3-Hydroxyproline levels with age. The biological significance is unclear but the level of 3-hydroxylation at the (GPP)n site appears to have increased as tendons evolved and shows both tendon type and developmental variations within a species.
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a novel 3 Hydroxyproline 3hyp rich motif marks the triple helical c terminus of tendon type i collagen
Journal of Biological Chemistry, 2011Co-Authors: David R Eyre, Maryann Weis, David M Hudson, Jiannjiu WuAbstract:Because of its unique physical and chemical properties, rat tail tendon collagen has long been favored for crystallographic and biochemical studies of fibril structure. In studies of the distribution of 3-Hydroxyproline in type I collagen of rat bone, skin, and tail tendon by mass spectrometry, the repeating sequences of Gly-Pro-Pro (GPP) triplets at the C terminus of α1(I) and α2(I) chains were shown to be heavily 3-hydroxylated in tendon but not in skin and bone. By isolating the tryptic peptides and subjecting them to Edman sequence analysis, the presence of repeating 3-Hydroxyprolines in consecutive GPP triplets adjacent to 4-Hydroxyproline was confirmed as a unique feature of the tendon collagen. A 1960s study by Piez et al. (Piez, K. A., Eigner, E. A., and Lewis, M. S. (1963) Biochemistry 2, 58–66) in which they compared the amino acid compositions of rat skin and tail tendon type I collagen chains indeed showed 3–4 residues of 3Hyp in tendon α1(I) and α2(I) chains but only one 3Hyp residue in skin α1(I) and none in α2(I). The present work therefore confirms this difference and localizes the additional 3Hyp to the GPP repeat at the C terminus of the triple-helix. We speculate on the significance in terms of a potential function in contributing to the unique assembly mechanism and molecular packing in tendon collagen fibrils and on mechanisms that could regulate 3-hydroxylation at this novel substrate site in a tissue-specific manner.
Adrienne E Clarke - One of the best experts on this subject based on the ideXlab platform.
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Hydroxyproline rich plant glycoproteins
Phytochemistry, 1998Co-Authors: Jens Sommerknudsen, Antony Bacic, Adrienne E ClarkeAbstract:This review summarizes the structures of the four major groups of Hydroxyproline-rich glycoproteins from plants; extensins, proline/Hydroxyproline-rich glycoproteins, arabinogalactan-proteins, and solanaceous lectins. Similarities and differences within and between the groups are discussed.
David R Eyre - One of the best experts on this subject based on the ideXlab platform.
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evolutionary origins of c terminal gpp n 3 Hydroxyproline formation in vertebrate tendon collagen
PLOS ONE, 2014Co-Authors: David M Hudson, Maryann Weis, Jiannjiu Wu, Rachel Werther, David R EyreAbstract:Approximately half the proline residues in fibrillar collagen are hydroxylated. The predominant form is 4-Hydroxyproline, which helps fold and stabilize the triple helix. A minor form, 3-Hydroxyproline, still has no clear function. Using peptide mass spectrometry, we recently revealed several previously unknown molecular sites of 3-Hydroxyproline in fibrillar collagen chains. In fibril-forming A-clade collagen chains, four new partially occupied 3-Hydroxyproline sites were found (A2, A3, A4 and (GPP)n) in addition to the fully occupied A1 site at Pro986. The C-terminal (GPP)n motif has five consecutive GPP triplets in α1(I), four in α2(I) and three in α1(II), all subject to 3-hydroxylation. The evolutionary origins of this substrate sequence were investigated by surveying the pattern of its 3-Hydroxyproline occupancy from early chordates through amphibians, birds and mammals. Different tissue sources of type I collagen (tendon, bone and skin) and type II collagen (cartilage and notochord) were examined by mass spectrometry. The (GPP)n domain was found to be a major substrate for 3-hydroxylation only in vertebrate fibrillar collagens. In higher vertebrates (mouse, bovine and human), up to five 3-Hydroxyproline residues per (GPP)n motif were found in α1(I) and four in α2(I), with an average of two residues per chain. In vertebrate type I collagen the modification exhibited clear tissue specificity, with 3-Hydroxyproline prominent only in tendon. The occupancy also showed developmental changes in Achilles tendon, with increasing 3-Hydroxyproline levels with age. The biological significance is unclear but the level of 3-hydroxylation at the (GPP)n site appears to have increased as tendons evolved and shows both tendon type and developmental variations within a species.
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a novel 3 Hydroxyproline 3hyp rich motif marks the triple helical c terminus of tendon type i collagen
Journal of Biological Chemistry, 2011Co-Authors: David R Eyre, Maryann Weis, David M Hudson, Jiannjiu WuAbstract:Because of its unique physical and chemical properties, rat tail tendon collagen has long been favored for crystallographic and biochemical studies of fibril structure. In studies of the distribution of 3-Hydroxyproline in type I collagen of rat bone, skin, and tail tendon by mass spectrometry, the repeating sequences of Gly-Pro-Pro (GPP) triplets at the C terminus of α1(I) and α2(I) chains were shown to be heavily 3-hydroxylated in tendon but not in skin and bone. By isolating the tryptic peptides and subjecting them to Edman sequence analysis, the presence of repeating 3-Hydroxyprolines in consecutive GPP triplets adjacent to 4-Hydroxyproline was confirmed as a unique feature of the tendon collagen. A 1960s study by Piez et al. (Piez, K. A., Eigner, E. A., and Lewis, M. S. (1963) Biochemistry 2, 58–66) in which they compared the amino acid compositions of rat skin and tail tendon type I collagen chains indeed showed 3–4 residues of 3Hyp in tendon α1(I) and α2(I) chains but only one 3Hyp residue in skin α1(I) and none in α2(I). The present work therefore confirms this difference and localizes the additional 3Hyp to the GPP repeat at the C terminus of the triple-helix. We speculate on the significance in terms of a potential function in contributing to the unique assembly mechanism and molecular packing in tendon collagen fibrils and on mechanisms that could regulate 3-hydroxylation at this novel substrate site in a tissue-specific manner.
Derek T A Lamport - One of the best experts on this subject based on the ideXlab platform.
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Hydroxyproline Assay Using NaBr/NaOCl
BIO-PROTOCOL, 2020Co-Authors: Derek T A LamportAbstract:(Abstract) Hydroxyproline (Hyp) is a major constituent of a relatively few proteins that are major structural components of the extracellular matrix and primary cell wall of animals and plants respectively. Significant amounts of the cyclic amino acids proline and Hydroxyproline decrease polypeptide flexibility; thus proline/Hydroxyproline-rich proteins are ideal scaffold components. Collagens typify animal tissues but extensins, arabinogalactan proteins (AGPs) and their close relatives, collectively referred to as Hydroxyproline-rich glycoproteins (HRGPs), typify plants (Lamport et al., 2011). While collagens are minimally glycosylated generally via a galactosyl hydroxylysine linkage, plant HRGP glycosylation involves short neutral oligosaccharides (in extensins) or much larger acidic polysaccharide substituents (in AGPs) O-linked via the Hydroxyproline hydroxyl group. Hydroxyproline assay is thus an integral part of their characterization and dominates the biochemical properties of these glycoproteins. The colourimetric assay described here quantifies free Hydroxyproline (e.g. released by acid hydrolysis) based on Kivirikko and Liesmma (1959) with hypobromite as an oxidant but modified by avoiding the use of hazardous liquid bromine. A number of oxidants have been used over the years, Vogel (1961, page 395) explains the preference for hypobromite as follows: "Hypochlorites tend to react slowly with reducing agents. Hypobromites although rather unstable when prepared directly from bromine and alkali, often react more rapidly; it is therefore advantageous to produce hypobromite in situ by adding an excess of bromide to the sample of hypochlorite:" OCl - + Br - OBr - + Cl - "By this means the relative stability of hypochlorite is combined with the more effective oxidizing properties of hypobromite."
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[55] Hydroxyproline glycosides in the plant kingdom
Methods in Enzymology, 2004Co-Authors: Derek T A LamportAbstract:Publisher Summary This chapter describes suitable methods for preparation and assay of Hydroxyproline arabinooligosaccharides and other Hydroxyproline glycosides. It discusses their biosynthesis, structure, incidentally indicating the diversity of Hydroxyproline glycosylation in the plant kingdom. The chapter also summarizes current approaches toward understanding the role of glycosylated Hydroxyproline residues in structural proteins. Hydroxyproline glycosides were discovered in Hydroxyproline-rich glycopeptides obtained by enzymic degradation of cell walls from cell suspension cultures. Complete characterization of Hydroxyproline glycosides defines the sugar conformation, anomeric configuration, and linkage analysis, achieved so far only for the tri- and tetraarabinosides isolated from tobacco cell walls. Methylation analysis defined the linkages and sugar conformation, while the acid lability also indicated furanosidic linkages. From their position outside the cell, their composition and structure, it can be argued that glycosylated Hydroxyproline-rich glycoproteins play a structural role in the extracellular matrix. Current approaches range from purely physiological correlations and stochastic molecular model building, to CD spectral comparisons of native extensin precursor before and after deglycosylation, and electron microscopy.
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A repetitive proline-rich protein from the gymnosperm douglas fir is a Hydroxyproline-rich glycoprotein.
Plant physiology, 1992Co-Authors: Marcia J Kieliszewski, R de Zacks, J F Leykam, Derek T A LamportAbstract:Intact cell elution of suspension cultures derived from Douglas fir, Pseudotsuga menziesii (Mirbel) Franco, yielded two extensin monomers, the first Hydroxyproline-rich glycoproteins (HRGPs) to be isolated from a gymnosperm. These HRGPs resolved on Superose-6 gel filtration. The smaller monomer was compositionally similar to angiosperm extensins like tomato P1. The larger monomer had a simple composition reminiscent of repetitive proline-rich proteins (RPRPs) from soybean cell walls and contained proline, Hydroxyproline, and sugar; hence designated a proline-Hydroxyproline-rich glycoprotein (PHRGP). The simple composition of the PHRGP implied a periodic structure which was confirmed by the simple chymotryptic map and 45-residue partial sequence of the major proline-Hydroxyproline-rich glycoprotein chymotryptide 5: Lys-Pro-Hyp-Val-Hyp-Val-Ile-Pro-Pro-Hyp-Val-Val-Lys-Pro-Hyp-Hyp-Val- Tyr-Lys-Pro-Hyp-Val-Hyp-Val-Ile-Pro-Pro-Hyp-Val-Val-Lys-Pro-Hyp-Hyp- Val-Tyr-Lys-Ile-Pro-Pro(Hyp)-Val-Ile-Lys-Pro. Proline-Hydroxyproline-rich glycoprotein chymotryptide 5 contained an 18-residue tandem repeat devoid of tetra(hydroxy)-proline or serine; it also contained two instances of the five-residue motif Hyp-Hyp-Val-Tyr-Lys and five of the general Pro-Pro-X-X-Lys motif, thereby establishing its homology with typical angiosperm RPRPs and extensins from tomato, petunia, carrot, tobacco, sugar beet, and Phaseolus. Unlike the nonglycosylated soybean RPRP, the highly purified Douglas fir PHRGP was lightly glycosylated, confirmed by a quantitative Hydroxyproline glycoside profile, indicating that extensins can range from highly glycosylated Hydroxyproline to little or no glycosylated Hydroxyproline. Comparison of extensin sequence data strongly indicates that a major determinant of Hydroxyproline glycosylation specificity is Hydroxyproline contiguity: extensins with tetraHydroxyproline blocks are very highly arabinosylated (>90% Hydroxyproline glycosylated), tri- and diHydroxyproline are less so, and single Hydroxyproline residues perhaps not at all. Despite high yields of extensins eluted from intact cells, the Douglas fir cell wall itself was Hydroxyproline poor yet remarkably rich in protein (>20%), again emphasizing the existence of other structural cell wall proteins that are neither HRGPs nor glycine-rich proteins.
Lexley Pinto M Pereira - One of the best experts on this subject based on the ideXlab platform.
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catharanthus roseus flower extract has wound healing activity in sprague dawley rats
BMC Complementary and Alternative Medicine, 2006Co-Authors: B S Nayak, Lexley Pinto M PereiraAbstract:Catharanthus roseus L (C. roseus) has been used to treat a wide assortment of diseases including diabetes. The objective of our study was to evaluate the antimicrobial and wound healing activity of the flower extract of Catharanthus in rats. Wound healing activity was determined in rats, after administration (100 mg kg-1 day-1) of the ethanol extract of C. roseus flower, using excision, incision and dead space wounds models. The animals were divided into two groups of 6 each in all the models. In the excision model, group 1 animals were topically treated with carboxymethyl cellulose as placebo control and group 2 received topical application of the ethanol extract of C. roseus at a dose of 100 mg/kg body weight/day. In an incision and dead space model group 1 animals were given normal saline and group 2 received the extract orally at a dose of 100 mg kg-1 day-1. Healing was assessed by the rate of wound contraction, period of epithelization, tensile strength (skin breaking strength), granulation tissue weight, and hydoxyproline content. Antimicrobial activity of the flower extract against four microorganisms was also assessed The extract of C. roseus significantly increased the wound breaking strength in the incision wound model compared with controls (P < 0.001). The extract-treated wounds were found to epithelialize faster, and the rate of wound contraction was significantly increased in comparison to control wounds (P < 0.001), Wet and dry granulation tissue weights, and Hydroxyproline content in a dead space wound model increased significantly (p < 0.05). Pseudomonas aeruginosa and Staphylococcus aureus demonstrated sensitivity to C. roseus Increased wound contraction and tensile strength, augmented Hydroxyproline content along with antimicrobial activity support the use of C. roseus in the topical management of wound healing.
