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F A Walker - One of the best experts on this subject based on the ideXlab platform.

  • nitric oxide binding to the ferri and ferroHeme states of nitrophorin 1 a reversible no binding Heme Protein from the saliva of the blood sucking insect rhodnius prolixus
    Journal of the American Chemical Society, 1999
    Co-Authors: X D Ding, John F Andersen, Andrzej Weichsel, Tatjana Kh Shokhireva, Celia A Balfour, Antonio J Pierik, B A Averill, William R Montfort, F A Walker
    Abstract:

    The recombinant NO-binding Heme Protein, nitrophorin 1 (NP1) from the saliva of the blood-sucking insect, Rhodnius prolixus, has been studied by spectroelectrochemistry, EPR, NMR, and FTIR spectros...

  • high affinity histamine binding and antihistaminic activity of the salivary nitric oxide carrying Heme Protein nitrophorin of rhodnius prolixus
    Journal of Experimental Medicine, 1994
    Co-Authors: José M. C. Ribeiro, F A Walker
    Abstract:

    The salivary glands of Rhodnius prolixus contain a nitrosyl-Heme Protein, named nitrophorin, that releases the vasodilatory and antiplatelet compound nitric oxide (NO). Because imidazole compounds such as histamine can interact with Fe(III) Heme Proteins, we investigated whether such substances could interact with Rhodnius nitrophorins. Both imidazole and histamine, but not histidine can produce full of the difference spectra of the Soret band in the 1-3 microM concentration range (at a Heme Protein concentration of 0.4 microM). The apparent K0.5 for the binding of histamine with the Heme Protein is below 1 microM. Furthermore, the complex histamine-Heme Protein does not dissociate after molecular sieving chromatography. To investigate whether histamine could displace NO from the native nitrosyl nitrophorins, histamine was added to the native Heme Proteins, leading to displacement of the bound NO as observed by changes in the absorption spectra as well as by the production of nitrite. Finally, the antihistamine effect of the Heme Protein was demonstrated by its inhibition of the histamine-provoked contractures of the guinea pig ileum. It is concluded that histamine, a common autacoid found at the site of injury and exposure to antigenic substances such as the site of feeding by hematophagous arthropods, can be scavenged by the nitrosyl nitrophorin of R. prolixus, which, in return, will release the vasodilatory and platelet inhibiting NO to counteract the host hemostatic response.

  • reversible binding of nitric oxide by a salivary Heme Protein from a bloodsucking insect
    Science, 1993
    Co-Authors: José M. C. Ribeiro, J M H Hazzard, Roberto Nussenzveig, Donald E Champagne, F A Walker
    Abstract:

    The bloodsucking bug Rhodnius prolixus has a salivary vasodilator, previously characterized as a nitrovasodilator, with salivary smooth muscle-relaxing and antiplatelet activity. Rhodnius salivary glands are bright red owing to the abundance of Heme Proteins. Electron paramagnetic resonance and optical spectroscopic experiments indicated that the salivary vasodilator is a nitrosylHeme Protein with an Fe(III) Heme that binds nitric oxide (NO) reversibly. Dilution of the Protein in neutral pH promoted NO release. This Protein thus appears to be the NO carrier that helps R. prolixus to feed on blood.

Michael S Tift - One of the best experts on this subject based on the ideXlab platform.

  • elevated carboxyhemoglobin in a marine mammal the northern elephant seal
    The Journal of Experimental Biology, 2014
    Co-Authors: Michael S Tift, Paul J Ponganis, Daniel E Crocker
    Abstract:

    Low concentrations of endogenous carbon monoxide (CO), generated primarily through degradation of Heme from Heme-Proteins, have been shown to maintain physiological function of organs and to exert cytoprotective effects. However, high concentrations of carboxyhemoglobin (COHb), formed by CO binding to hemoglobin, potentially prevent adequate O2 delivery to tissues by lowering arterial O2 content. Elevated Heme-Protein concentrations, as found in marine mammals, are likely associated with greater Heme degradation, more endogenous CO production and, consequently, elevated COHb concentrations. Therefore, we measured COHb in elephant seals, a species with large blood volumes and elevated hemoglobin and myoglobin concentrations. The levels of COHb were positively related to the total hemoglobin concentration. The maximum COHb value was 10.4% of total hemoglobin concentration. The mean (±s.e.m.) value in adult seals was 8.7±0.3% (N=6), while juveniles and pups (with lower Heme-Protein contents) had lower mean COHb values of 7.6±0.2% and 7.1±0.3%, respectively (N=9 and N=9, respectively). Serial samples over several hours revealed little to no fluctuation in COHb values. This consistent elevation in COHb suggests that the magnitude and/or rate of Heme-Protein turnover is much higher than in terrestrial mammals. The maximum COHb values from this study decrease total body O2 stores by 7%, thereby reducing the calculated aerobic dive limit for this species. However, the constant presence of elevated CO in blood may also protect against potential ischemia–reperfusion injury associated with the extreme breath-holds of elephant seals. We suggest the elephant seal represents an ideal model for understanding the potential cytoprotective effects, mechanisms of action and evolutionary adaptation associated with chronically elevated concentrations of endogenously produced CO.

  • elevated carboxyhemoglobin in a marine mammal the northern elephant seal
    The Journal of Experimental Biology, 2014
    Co-Authors: Michael S Tift, Paul J Ponganis, Daniel E Crocker
    Abstract:

    Low concentrations of endogenous carbon monoxide (CO), generated primarily through degradation of Heme from Heme-Proteins, have been shown to maintain physiological function of organs and to exert cytoprotective effects. However, high concentrations of carboxyhemoglobin (COHb), formed by CO binding to hemoglobin, potentially prevent adequate O2 delivery to tissues by lowering arterial O2 content. Elevated Heme-Protein concentrations, as found in marine mammals, are likely associated with greater Heme degradation, more endogenous CO production and, consequently, elevated COHb concentrations. Therefore, we measured COHb in elephant seals, a species with large blood volumes and elevated hemoglobin and myoglobin concentrations. The levels of COHb were positively related to the total hemoglobin concentration. The maximum COHb value was 10.4% of total hemoglobin concentration. The mean (±s.e.m.) value in adult seals was 8.7±0.3% (N=6), while juveniles and pups (with lower Heme-Protein contents) had lower mean COHb values of 7.6±0.2% and 7.1±0.3%, respectively (N=9 and N=9, respectively). Serial samples over several hours revealed little to no fluctuation in COHb values. This consistent elevation in COHb suggests that the magnitude and/or rate of Heme-Protein turnover is much higher than in terrestrial mammals. The maximum COHb values from this study decrease total body O2 stores by 7%, thereby reducing the calculated aerobic dive limit for this species. However, the constant presence of elevated CO in blood may also protect against potential ischemia–reperfusion injury associated with the extreme breath-holds of elephant seals. We suggest the elephant seal represents an ideal model for understanding the potential cytoprotective effects, mechanisms of action and evolutionary adaptation associated with chronically elevated concentrations of endogenously produced CO.

Mark T Gladwin - One of the best experts on this subject based on the ideXlab platform.

Daniel E Crocker - One of the best experts on this subject based on the ideXlab platform.

  • elevated carboxyhemoglobin in a marine mammal the northern elephant seal
    The Journal of Experimental Biology, 2014
    Co-Authors: Michael S Tift, Paul J Ponganis, Daniel E Crocker
    Abstract:

    Low concentrations of endogenous carbon monoxide (CO), generated primarily through degradation of Heme from Heme-Proteins, have been shown to maintain physiological function of organs and to exert cytoprotective effects. However, high concentrations of carboxyhemoglobin (COHb), formed by CO binding to hemoglobin, potentially prevent adequate O2 delivery to tissues by lowering arterial O2 content. Elevated Heme-Protein concentrations, as found in marine mammals, are likely associated with greater Heme degradation, more endogenous CO production and, consequently, elevated COHb concentrations. Therefore, we measured COHb in elephant seals, a species with large blood volumes and elevated hemoglobin and myoglobin concentrations. The levels of COHb were positively related to the total hemoglobin concentration. The maximum COHb value was 10.4% of total hemoglobin concentration. The mean (±s.e.m.) value in adult seals was 8.7±0.3% (N=6), while juveniles and pups (with lower Heme-Protein contents) had lower mean COHb values of 7.6±0.2% and 7.1±0.3%, respectively (N=9 and N=9, respectively). Serial samples over several hours revealed little to no fluctuation in COHb values. This consistent elevation in COHb suggests that the magnitude and/or rate of Heme-Protein turnover is much higher than in terrestrial mammals. The maximum COHb values from this study decrease total body O2 stores by 7%, thereby reducing the calculated aerobic dive limit for this species. However, the constant presence of elevated CO in blood may also protect against potential ischemia–reperfusion injury associated with the extreme breath-holds of elephant seals. We suggest the elephant seal represents an ideal model for understanding the potential cytoprotective effects, mechanisms of action and evolutionary adaptation associated with chronically elevated concentrations of endogenously produced CO.

  • elevated carboxyhemoglobin in a marine mammal the northern elephant seal
    The Journal of Experimental Biology, 2014
    Co-Authors: Michael S Tift, Paul J Ponganis, Daniel E Crocker
    Abstract:

    Low concentrations of endogenous carbon monoxide (CO), generated primarily through degradation of Heme from Heme-Proteins, have been shown to maintain physiological function of organs and to exert cytoprotective effects. However, high concentrations of carboxyhemoglobin (COHb), formed by CO binding to hemoglobin, potentially prevent adequate O2 delivery to tissues by lowering arterial O2 content. Elevated Heme-Protein concentrations, as found in marine mammals, are likely associated with greater Heme degradation, more endogenous CO production and, consequently, elevated COHb concentrations. Therefore, we measured COHb in elephant seals, a species with large blood volumes and elevated hemoglobin and myoglobin concentrations. The levels of COHb were positively related to the total hemoglobin concentration. The maximum COHb value was 10.4% of total hemoglobin concentration. The mean (±s.e.m.) value in adult seals was 8.7±0.3% (N=6), while juveniles and pups (with lower Heme-Protein contents) had lower mean COHb values of 7.6±0.2% and 7.1±0.3%, respectively (N=9 and N=9, respectively). Serial samples over several hours revealed little to no fluctuation in COHb values. This consistent elevation in COHb suggests that the magnitude and/or rate of Heme-Protein turnover is much higher than in terrestrial mammals. The maximum COHb values from this study decrease total body O2 stores by 7%, thereby reducing the calculated aerobic dive limit for this species. However, the constant presence of elevated CO in blood may also protect against potential ischemia–reperfusion injury associated with the extreme breath-holds of elephant seals. We suggest the elephant seal represents an ideal model for understanding the potential cytoprotective effects, mechanisms of action and evolutionary adaptation associated with chronically elevated concentrations of endogenously produced CO.

Yingwu Lin - One of the best experts on this subject based on the ideXlab platform.

  • design of artificial metalloProteins metalloenzymes by tuning noncovalent interactions
    Journal of Biological Inorganic Chemistry, 2018
    Co-Authors: Shun Hirota, Yingwu Lin
    Abstract:

    Noncovalent weak interactions [hydrophobic interaction and hydrogen (H)-bond] play crucial roles in controlling the functions of biomolecules, and thus have been used to design artificial metalloProteins/metalloenzymes during the past few decades. In this review, we focus on the recent progresses in Protein design by tuning the noncovalent interactions, including hydrophobic and H-bonding interactions. The topics include redesign and reuse of the Heme pocket and other Protein scaffolds, design of the Heme Protein interface, and de novo design of metalloProteins. The informations not only give insights into the metalloenzyme reaction mechanisms but also provide new reactions for future applications.

  • rational Heme Protein design all roads lead to rome
    ChemInform, 2014
    Co-Authors: Yingwu Lin, Elizabeth B Sawyer, Jiangyun Wang
    Abstract:

    Review: modification of the Heme-binding active site and the Heme group, Protein hybridization and domain swapping, and de novo design; 113 refs.

  • rational Heme Protein design all roads lead to rome
    Chemistry-an Asian Journal, 2013
    Co-Authors: Yingwu Lin, Elizabeth B Sawyer, Jiangyun Wang
    Abstract:

    Heme Proteins are among the most abundant and important metalloProteins, exerting diverse biological functions including oxygen transport, small molecule sensing, selective C-H bond activation, nitrite reduction, and electron transfer. Rational Heme Protein designs focus on the modification of the Heme-binding active site and the Heme group, Protein hybridization and domain swapping, and de novo design. These strategies not only provide us with unique advantages for illustrating the structure-property-reactivity-function (SPRF) relationship of Heme Proteins in nature but also endow us with the ability to create novel biocatalysts and biosensors.