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PubMed1988

A hydroxyproline-rich protein in the soybean cell wall.

A cDNA clone that hybridizes to an mRNA (1A10) that accumulates to a substantial level in the axis of the germinating soybean seed was sequenced. The amino acid sequence of the clone indicates an almost perfect repeat of Pro-Pro-Val-Tyr-Lys resulting in a protein containing 40% proline and lacking serine and histidine. On the likelihood that such a protein might be a hydroxyproline-rich cell-wall glycoprotein (HRGP), cell walls of a soybean cell culture were extracted by procedures used to obtain soluble basic cell-wall glycoproteins, and the proteins were fractionated and purified. A 33-kDa protein (and possibly a 28-kDa protein) was obtained that has an amino acid distribution similar to that of the cDNA clone. The protein lacks histidine and serine and contains 20% hydroxyproline and 20% proline. The HRGP is thus distinct both in its amino acid content and in its pentameric repeat of Pro-Pro-Val-Tyr-Lys, with half of the prolines being hydroxylated.

Amino Acid Sequence↗

PubMed1999

Evidence for 4-hydroxyproline in viral proteins. Characterization of a viral prolyl 4-hydroxylase and its peptide substrates.

4-Hydroxyproline, the characteristic amino acid of collagens and collagen-like proteins in animals, is also found in certain proline-rich proteins in plants but has been believed to be absent from viral and bacterial proteins. We report here on the cloning and characterization from a eukaryotic algal virus, Paramecium bursaria Chlorella virus-1, of a 242-residue polypeptide, which shows distinct sequence similarity to the C-terminal half of the catalytic alpha subunits of animal prolyl 4-hydroxylases. The recombinant polypeptide, expressed in Escherichia coli, was found to be a soluble monomer and to hydroxylate both (Pro-Pro-Gly)(10) and poly(L-proline), the standard substrates of animal and plant prolyl 4-hydroxylases, respectively. Synthetic peptides such as (Pro-Ala-Pro-Lys)(n), (Ser-Pro-Lys-Pro-Pro)(5), and (Pro-Glu-Pro-Pro-Ala)(5) corresponding to proline-rich repeats coded by the viral genome also served as substrates. (Pro-Ala-Pro-Lys)(10) was a particularly good substrate, with a K(m) of 20 microM. The prolines in both positions in this repeat were hydroxylated, those preceding the alanines being hydroxylated more efficiently. The data strongly suggest that P. bursaria Chlorella virus-1 expresses proteins in which many prolines become hydroxylated to 4-hydroxyproline by a novel viral prolyl 4-hydroxylase.

Amino Acid Sequence↗

PubMed1999

Response to the sexual pheromone and wounding in the green alga volvox: induction of an extracellular glycoprotein consisting almost exclusively of hydroxyproline.

The extracellular matrix (ECM) of Volvox is modified during development or in response to external stimuli, like the sex-inducing pheromone. It has recently been demonstrated that a number of genes triggered by the sex-inducing pheromone are also inducible by wounding. By differential screening of a cDNA library, a novel gene was identified that is transcribed in response to the pheromone. Its gene product was characterized as an ECM glycoprotein with a striking feature: it exhibits a hydroxyproline content of 68% and therefore is an extreme member of the family of hydroxyproline-rich glycoproteins (HRGPs). HRGPs are known as constituents of higher plant ECMs and seem to function as structural barriers in defense responses. The Volvox HRGP is also found to be inducible by wounding. This indicates that the wound response scenarios of higher plants and multicellular green algae may be evolutionary related.

Algal Proteins↗

PubMedDate not supplied

Personal exposure and health effect relationship for NO2 with urinary hydroxyproline to creatinine ratio as indicator.

Establishment of an exposure-effect relationship was attempted between personal nitrogen dioxide (NO2) exposure and urinary hydroxyproline to creatinine ratio of approximately 800 adult women, who were mothers of primary schoolchildren living in two communities around Tokyo. Daily average of the personal NO2 exposure (ENO2) was measured during wintertime by a newly developed personal monitor exposed for 24 hours. The hydroxyproline to creatinine ratio (HOP:C) in the urine sample collected early in the morning of the day for ENO2 measurement was used as a biochemical indicator of the health effect of NO2 exposure. The HOP:C was found to have significant correlation with ENO2 and number of cigarettes smoked actively and passively. ENO2, however, had no correlation with the intensity of the smoking levels; they might affect HOP:C independently. Stepwise multiple regression analysis revealed that HOP:C could be predicted by ENO2 and smoking habits at a high confidence level. The regression analysis of the active smokers' group indicated that a few cigarettes was enough to increase the HOP:C, while in the case of passive smoking, HOP:C increased proportionally to the number of cigarettes.

Adult↗

PubMedDate not supplied

Changes in plasma urate, creatinine, alkaline phosphatase and the 24 hours excretion of hydroxyproline during sexual maturation in adolescents.

The relative concentrations of plasma uric acid and creatinine, the alkaline phosphatase activities and the 24 hour urinary excretion of hydroxyproline together with sexual maturity ratings are reported in a population of normal British schoolchildren studied longitudinally over a three-year period. The children were all of European origin and their ages ranged from 7 to 17 years. Plasma urate rose sharply during puberty in the boys but not in the girls. Plasma creatinine rose in both sexes during maturation. Plasma alkaline phosphatase activity rose to a peak at genital maturity 3(G3) in boys and breast maturity 2(B2) in girls and subsequently fell rapidly in both sexes. The 24-hour urinary secretion of hydroxyproline was high in young boys and rose to a peak during G3 and G4 and then fell rapidly. In girls there was no significant peak in concentrations, although there was a fall during B4 and B5, and levels were higher throughout puberty than those reported for adult females.

Adolescent↗

PubMed1975

cis-hydroxyproline limits work necessary to flex a digit after tendon injury.

Present surgical procedures for the repair of tendon injury are complicated by formation of peritendinous collagenous adhesions which restrict tendon gliding. Several sensitive biomechanical tests have been developed to quantitate peritendinous restriction of gliding. Using these tests it was found that cis-hydroxyproline significantly limits net collagen accumulation following tendon injury in a rat model and decreases the adhesive restraints to tendon gliding. cis-Hydroxyproline and other proline analoques offer a method for specifically preventing excessive collagen formation.

Animals↗

PubMed1978

Relationship of the activity of the bone isoenzyme of serum alkaline phosphatase to urinary hydroxyproline excretion in metabolic and neoplastic bone diseases.

A significant correlation between the activity of the bone isoenzyme or serum alkaline phosphatase and the urinary hydroxyproline excretion in osteomalacia, osteoporosis, primary hyperparathyroidism with osteodystrophy, Paget's disease, secondary bone tumours, and in a control group was found (P less than 0.001). This close correlation was not observed between these variables in patients with active acromegaly. Diagnosis determined from these indices of formation and turnover of bone matrix agreed with that established by histological and histochemical examination of bone, by X-ray investigation of the skeleton, and by the radionuclear 85Sr test. The relationship between the activity of bone isoenzyme and urinary hydroxyproline excretion differed in metabolic bone diseases with a high bone turnover, in patients with osteoporosis and in patients with early osteoclastic bone metastases.

Acromegaly↗

PubMed2005

Experimental determination of proline hydroxylation and hydroxyproline arabinogalactosylation motifs in secretory proteins.

Many secretory and several vacuolar proteins in higher plants contain hydroxylated proline residues. In many cases, hydroxyprolines in proteins are glycosylated with either arabinogalactan or oligoarabinose. We have previously shown that a sporamin precursor is O-glycosylated at the hydroxylated proline 36 residue with an arabinogalactan-type glycan when this protein is expressed in tobacco BY-2 cells (Matsuoka et al., 1995). Taking advantage of the fact that this is the only site of proline hydroxylation and glycosylation in sporamin, we analyzed the amino acid requirement for proline hydroxylation and arabinogalactosylation. We expressed several deletion constructs and many amino acid substitution mutants in tobacco cells and analyzed glycosylation and proline hydroxylation of the expressed sporamins. Hydroxylation of a proline residue requires the five amino acid sequence [AVSTG]-Pro-[AVSTGA]-[GAVPSTC]-[APS or acidic] (where Pro is the modification site) and glycosylation of hydroxyproline (Hyp) requires the seven amino acid sequence [not basic]-[not T]-[neither P, T, nor amide]-Hyp-[neither amide nor P]-[not amide]-[APST], although charged amino acids at the -2 position and basic amide residues at the +1 position relative to the modification site seem to inhibit the elongation of the arabinogalactan side chain. Based on the combination of these two requirements, we concluded that the sequence motif for efficient arabinogalactosylation, including the elongation of the glycan side chain, is [not basic]-[not T]-[AVSG]-Pro-[AVST]-[GAVPSTC]-[APS].

Amino Acid Motifs↗

PubMed1977

The synthesis of macromolecular 3-hydroxyproline by attaching and confluent cultures of human fibroblasts.

The synthesis of collagen has been studied during the attachment of freshly trypsinized human fibroblasts to culture vessels by measurement of the incorporation of radioactive proline into macromolecular hydroxyproline. Collagenous protein(s) was found to be a component of a substrate-attached material ('microexudate carpet') synthesized rapidly during cell attachment in the absence of serum. The ratio of 3-hydroxyproline/4-hydroxyproline in the collagenous proteins synthesized during cell attachment was found to be 4-5 fold higher than that of normal type I collagen. The synthesis of 3-hydroxyproline by confluent cultures was diminished by serum deprivation, and was shown to require higher concentrations of ascorbate than the synthesis of the 4-hydroxy isomer.

Ascorbic Acid↗

PubMed1988

The variation in cervical hydroxyproline and cervical water with age.

The squamocolumnar junction is frequently not visible in the postmenopausal patient. This study attempts to identify some of the changes in the cervix that may account for this observation. Twenty-four cervical biopsy samples taken at the squamocolumnar junction were analysed for hydroxyproline (collagen) and water content. There was significantly more hydroxyproline (collagen) in the premenopausal woman than the postmenopausal woman. Similarly, there was higher percentage of water in the biopsies in the premenopausal woman than the postmenopausal woman. Further samples obtained deeper in the cervical stroma did not confirm these differences. It appears likely that differences in cervical water and cervical collagen near the surface of the cervix account, at least in part, for the lack of visibility of the squamocolumnar junction in the older woman.

Adult↗

PubMed1979

Mechanical properties and hydroxyproline content of connective tissue in porous ceramic implants.

The present study describes a model applying ceramic implants (A1203) for in vivo studies of connective tissue regeneration. Two types of implants have been developed: a one-piece model for histological examination and chemical analyses, and a two-piece implant which can also be used for mechanical testing of connective tissue. When these were implanted subcutaneoulsly on the back of rats, a correlation was found between the mechanical strength and the hydroxyproline content of connective tissue in the implants. The peak synthesis occurred between the 7th and the 14th day after implantation, and a plateau was reached for both strength-increases and hydroxyproline-formation between the 14th and the 21st days. For histological examination, the implants were embedded in plastic materials and prepared as hard tissue specimens. The model presented can be applied to study connective tissue regeneration in normal and pathological conditions, including studies of the effects of various drugs on the connective tissue.

Aluminum Oxide↗

PubMed1990

Assessment of bone turnover in the dry period of dairy cows by measurement of plasma bone GLA protein, total plasma alkaline phosphatase activity and urinary hydroxyproline.

Plasma osteocalcin, or plasma bone GLA protein (BGP), total plasma alkaline phosphatase activity and urinary hydroxyproline excretion of twenty-four pregnant dairy cows (thirteen in their first or second pregnancy, i.e. low parity, and eleven in their third or more pregnancies, i.e. high parity) were measured from 7 weeks before parturition until 1 week after parturition. Seven weeks before parturition the cows' ration was changed to one containing either 0.22% magnesium (low magnesium, LMg) or 0.82% magnesium (high magnesium, HMg) in the dry matter, and the potassium content of both rations was increased to approximately 4.1% in the dry matter to reduce the absorption of magnesium. Plasma BGP levels decreased significantly (P less than 0.01) as parturition approached while total plasma alkaline phosphatase activity and urinary hydroxyproline excretion did not. Magnesium supply and parity had no significant effect on this decrease. The overall plasma concentration of BGP, total plasma alkaline phosphatase activity and the urinary hydroxyproline/creatinine ratio in the prepartum period were affected by parity (P less than 0.05) with higher values in the lower parity cows. A significant positive correlation (r = 0.58, P less than 0.01) was found in all cows between plasma BGP level at parturition and the percentage of the bone surface covered with osteoblasts; however, plasma BGP was not correlated either with other histomorphometric variables or with total alkaline phosphatase activity during this time.

Alkaline Phosphatase↗

PubMed2002

Structure of an HIF-1alpha -pVHL complex: hydroxyproline recognition in signaling.

The ubiquitination of the hypoxia-inducible factor (HIF) by the von Hippel-Lindau tumor suppressor (pVHL) plays a central role in the cellular response to changes in oxygen availability. pVHL binds to HIF only when a conserved proline in HIF is hydroxylated, a modification that is oxygen-dependent. The 1.85 angstrom structure of a 20-residue HIF-1alpha peptide-pVHL-ElonginB-ElonginC complex shows that HIF-1alpha binds to pVHL in an extended beta strand-like conformation. The hydroxyproline inserts into a gap in the pVHL hydrophobic core, at a site that is a hotspot for tumorigenic mutations, with its 4-hydroxyl group recognized by buried serine and histidine residues. Although the beta sheet-like interactions contribute to the stability of the complex, the hydroxyproline contacts are central to the strict specificity characteristic of signaling.

Amino Acid Sequence↗

PubMed1970

Properties of the inducible hydroxyproline transport system of Pseudomonas putida.

Features of the transport system for hydroxyproline in a strain of Pseudomonas putida were studied. A mutant, lacking hydroxyproline-2 epimerase and unable to metabolize hydroxy-l-proline, was shown to transport and accumulate this compound after induction. Both entry and exit rates were examined, and kinetic constants for the reaction were determined. Increasing the induction time from 0.5 to 3 hr increased the entry rate three- to fourfold but had only a small and variable effect on the exit rate. Entry followed saturation kinetics. For hydroxy-l-proline, the K(m) and V(max) values were found to be 3 x 10(-5)m and 6 mumoles per g (dry weight) per min, respectively. The K(m) and V(max) for the epimer allohydroxy-d-proline were 10(-3)m and 0.1 mumole per g (dry weight) per min. Entry rates into "loaded" and "unloaded" cells were found to be the same. Exit was shown to be first order over the range of internal substrate concentrations measured. Exit rates were measured by several different methods and found to be independent of external substrate concentration. The first-order exit rate constant was computed to be 0.23 min(-1). Several metabolic inhibitors were examined for their effect on transport. The inhibitory action of N-ethyl maleimide was shown to be greatly reduced if cells were allowed to accumulate hydroxy-l-proline before exposure to the inhibitor. A number of other amino acids interfered with the transport of hydroxy-l-proline; the greatest effect was produced by l-alanine and l-proline.

Amino Acids↗

PubMed1989

Hydroxyproline in the major capsid protein VP1 of polyomavirus.

Amino acid analysis of [3H]proline-labeled polyomavirus major capsid protein VP1 by two-dimensional paper chromatography of the acid-hydrolyzed protein revealed the presence of 3H-labeled hydroxyproline. Addition of the proline analog L-azetidine-2-carboxylic acid to infected mouse kidney cell cultures prevented or greatly reduced hydroxylation of proline in VP1. Immunofluorescence analysis performed on infected cells over a time course of analog addition revealed that virus proteins were synthesized but that transport from the cytoplasm to the nucleus was impeded. A reduction in the assembly of progeny virions demonstrated by CsCl gradient purification of virus from [35S]methionine-labeled infected cell cultures was found to correlate with the time of analog addition. These results suggest that incorporation of this proline analog into VP1, accompanied by reduction of the hydroxyproline content of the protein, influences the amount of virus progeny produced by affecting transport of VP1 to the cell nucleus for assembly into virus particles.

Amino Acids↗

PubMed1976

Relation of urinary total hydroxyproline: Creatinine ratio to height velocity in children with retarded growth.

The urinary total hydroxyproline:creatinine ratio was measured on samples collected from 18 boys and 11 girls referred to a children's hospital because of small stature. Any serious degree of growth hormone deficiency was excluded and each child's growth and development was recorded over the following year. The hypothesis that the average hydroxyproline:creatinine ratio on random urine samples may be used to predict height velocity was examined. Such a prediction would have been incorrect on 35% of occasions, and it is concluded that this investigation cannot be used reliability to predict growth in height; it is probably only useful with sequential studies of an individual child over short periods while monitoring therapy.

Adolescent↗

PubMed1981

Hydroxyproline-rich protein in the capsule of a strain of Staphylococcus aureus.

A protein fraction containing a high amount of hydroxyproline was found in the capsule of the Smith diffuse strain (encapsulated) when compared with that of dialysate medium. This content varied depending upon temperature, oxygen supply, sodium chloride, and carbohydrates. The hydroxyproline content of the single proteinaceous fraction, obtained by Sephadex G-200 column chromatography, was one fourth of the total amino acid composition.

Amino Acids↗

PubMed1980

Urinary 3-hydroxyproline in renal disease.

The renal excretion of 3-hydroxyproline (3-HYP), an isomer of 4-hydroxyproline (4-HYP) found 6-10 times more in basement membrane collagen than in interstitial collagen, was investigated in control subjects and in 58 adult patients with various kidney diseases. With the exception of polykystic renal disease, all the nephropathies were investigated by renal biopsy. In normal adult subjects urinary 3-HYP was 12.5 +/- 3.5 (SD) mumol/24 h, 4-HYP 226 +/- 62 mumol/24 h and the percentage ratio 3-HYP/4-HYP 5.5 +/- 0.5. This ratio was twice as little during growth because of a relative excess of 4-HYP. In patients with acute glomerular disease (acute and subacute glomerulonephritis, lupus nephritis...) (n = 13) 3-HYP was 17.1 +/- 5.8 mumol/24 h (p less than 0.01 when compared with the normal) and 4-HYP 234 +/- 77 mumol/24 h. The ratio between the two values was 7.3 +/- 0.7 (p less than 0.001). Such an increase in 3-HYP was not observed in patients with chronic glomerulonephritis (n = 24) where 3-HYP was 9.6 +/- 5.7 mumol/24 h and 3-HYP/4-HYP 6.0 +/- 1.6, neither in patients with diabetic glomerulonephritis (n = 6). In chronic interstitial nephritis (n = 8) the 3-HYP/4-HYP ratio was decreased with the exception of polykystic renal diseases (PKD), where it was increased (p less than 0.001). The daily urinary contents of 3-HYP and 4-HYP were slightly altered by renal insufficiency. In glomerulonephritis with nephrotic syndrome whatever the histological lesions, urinary 3-HYP did not change significantly. These preliminary results indicate that urinary 3-HYP (1) is increased when glomerulonephritis is clinically acute or subacute; (2) is increased in PKD suggesting a possible inborn error of collagen metabolism.

Adolescent↗