1
|
Petersen CE, Sun J, Silva K, Kosmach A, Balaban RS, Murphy E. Increased mitochondrial free Ca 2+ during ischemia is suppressed, but not eliminated by, germline deletion of the mitochondrial Ca 2+ uniporter. Cell Rep 2023; 42:112735. [PMID: 37421627 PMCID: PMC10529381 DOI: 10.1016/j.celrep.2023.112735] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2022] [Revised: 04/20/2023] [Accepted: 06/18/2023] [Indexed: 07/10/2023] Open
Abstract
Mitochondrial Ca2+ overload is proposed to regulate cell death via opening of the mitochondrial permeability transition pore. It is hypothesized that inhibition of the mitochondrial Ca2+ uniporter (MCU) will prevent Ca2+ accumulation during ischemia/reperfusion and thereby reduce cell death. To address this, we evaluate mitochondrial Ca2+ in ex-vivo-perfused hearts from germline MCU-knockout (KO) and wild-type (WT) mice using transmural spectroscopy. Matrix Ca2+ levels are measured with a genetically encoded, red fluorescent Ca2+ indicator (R-GECO1) using an adeno-associated viral vector (AAV9) for delivery. Due to the pH sensitivity of R-GECO1 and the known fall in pH during ischemia, hearts are glycogen depleted to decrease the ischemic fall in pH. At 20 min of ischemia, there is significantly less mitochondrial Ca2+ in MCU-KO hearts compared with MCU-WT controls. However, an increase in mitochondrial Ca2+ is present in MCU-KO hearts, suggesting that mitochondrial Ca2+ overload during ischemia is not solely dependent on MCU.
Collapse
Affiliation(s)
- Courtney E Petersen
- Cardiovascular Branch, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, MD 20892, USA
| | - Junhui Sun
- Cardiovascular Branch, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, MD 20892, USA
| | - Kavisha Silva
- Cardiovascular Branch, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, MD 20892, USA
| | - Anna Kosmach
- Cardiovascular Branch, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, MD 20892, USA
| | - Robert S Balaban
- Systems Biology Center, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, MD 20892, USA
| | - Elizabeth Murphy
- Cardiovascular Branch, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, MD 20892, USA.
| |
Collapse
|
2
|
Saoji M, Petersen CE, Sen A, Tripoli BA, Smyth JT, Cox RT. Reduction of Drosophila Mitochondrial RNase P in Skeletal and Heart Muscle Causes Muscle Degeneration, Cardiomyopathy, and Heart Arrhythmia. Front Cell Dev Biol 2022; 10:788516. [PMID: 35663400 PMCID: PMC9162060 DOI: 10.3389/fcell.2022.788516] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2021] [Accepted: 04/14/2022] [Indexed: 11/19/2022] Open
Abstract
In this study, we examine the cause and progression of mitochondrial diseases linked to the loss of mtRNase P, a three-protein complex responsible for processing and cleaving mitochondrial transfer RNAs (tRNA) from their nascent transcripts. When mtRNase P function is missing, mature mitochondrial tRNA levels are decreased, resulting in mitochondrial dysfunction. mtRNase P is composed of Mitochondrial RNase P Protein (MRPP) 1, 2, and 3. MRPP1 and 2 have their own enzymatic activity separate from MRPP3, which is the endonuclease responsible for cleaving tRNA. Human mutations in all subunits cause mitochondrial disease. The loss of mitochondrial function can cause devastating, often multisystemic failures. When mitochondria do not provide enough energy and metabolites, the result can be skeletal muscle weakness, cardiomyopathy, and heart arrhythmias. These symptoms are complex and often difficult to interpret, making disease models useful for diagnosing disease onset and progression. Previously, we identified Drosophila orthologs of each mtRNase P subunit (Roswell/MRPP1, Scully/MRPP2, Mulder/MRPP3) and found that the loss of each subunit causes lethality and decreased mitochondrial tRNA processing in vivo. Here, we use Drosophila to model mtRNase P mitochondrial diseases by reducing the level of each subunit in skeletal and heart muscle using tissue-specific RNAi knockdown. We find that mtRNase P reduction in skeletal muscle decreases adult eclosion and causes reduced muscle mass and function. Adult flies exhibit significant age-progressive locomotor defects. Cardiac-specific mtRNase P knockdowns reduce fly lifespan for Roswell and Scully, but not Mulder. Using intravital imaging, we find that adult hearts have impaired contractility and exhibit substantial arrhythmia. This occurs for roswell and mulder knockdowns, but with little effect for scully. The phenotypes shown here are similar to those exhibited by patients with mitochondrial disease, including disease caused by mutations in MRPP1 and 2. These findings also suggest that skeletal and cardiac deficiencies induced by mtRNase P loss are differentially affected by the three subunits. These differences could have implications for disease progression in skeletal and heart muscle and shed light on how the enzyme complex functions in different tissues.
Collapse
Affiliation(s)
- Maithili Saoji
- Department of Biochemistry and Molecular Biology, Uniformed Services University, Bethesda, MD, United States
- Henry M. Jackson Foundation, Bethesda, MD, United States.
| | - Courtney E. Petersen
- Henry M. Jackson Foundation, Bethesda, MD, United States.
- Department of Anatomy, Physiology and Genetics, Uniformed Services University, Bethesda, MD, United States
| | - Aditya Sen
- Department of Biochemistry and Molecular Biology, Uniformed Services University, Bethesda, MD, United States
- Henry M. Jackson Foundation, Bethesda, MD, United States.
| | - Benjamin A. Tripoli
- Department of Anatomy, Physiology and Genetics, Uniformed Services University, Bethesda, MD, United States
| | - Jeremy T. Smyth
- Department of Anatomy, Physiology and Genetics, Uniformed Services University, Bethesda, MD, United States
| | - Rachel T. Cox
- Department of Biochemistry and Molecular Biology, Uniformed Services University, Bethesda, MD, United States
| |
Collapse
|
3
|
Petersen CE, Tripoli BA, Schoborg TA, Smyth JT. Analysis of Drosophila cardiac hypertrophy by microcomputerized tomography for genetic dissection of heart growth mechanisms. Am J Physiol Heart Circ Physiol 2022; 322:H296-H309. [PMID: 34951542 PMCID: PMC8782661 DOI: 10.1152/ajpheart.00387.2021] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
Heart failure is often preceded by pathological cardiac hypertrophy, a thickening of the heart musculature driven by complex gene regulatory and signaling processes. The Drosophila heart has great potential as a genetic model for deciphering the underlying mechanisms of cardiac hypertrophy. However, current methods for evaluating hypertrophy of the Drosophila heart are laborious and difficult to carry out reproducibly. Here, we demonstrate that microcomputerized tomography (microCT) is an accessible, highly reproducible method for nondestructive, quantitative analysis of Drosophila heart morphology and size. To validate our microCT approach for analyzing Drosophila cardiac hypertrophy, we show that expression of constitutively active Ras (Ras85DV12), previously shown to cause hypertrophy of the fly heart, results in significant thickening of both adult and larval heart walls when measured from microCT images. We then show using microCT analysis that genetic upregulation of store-operated Ca2+ entry (SOCE) driven by expression of constitutively active Stim (StimCA) or Orai (OraiCA) proteins also results in significant hypertrophy of the Drosophila heart, through a process that specifically depends on Orai Ca2+ influx channels. Intravital imaging of heart contractility revealed significantly reduced end-diastolic and end-systolic dimensions in StimCA- and OraiCA-expressing hearts, consistent with the hypertrophic phenotype. These results demonstrate that increased SOCE activity is an important driver of hypertrophic cardiomyocyte growth, and demonstrate how microCT analysis combined with tractable genetic tools in Drosophila can be used to delineate molecular signaling processes that underlie cardiac hypertrophy and heart failure.NEW & NOTEWORTHY Genetic analysis of Drosophila cardiac hypertrophy holds immense potential for the discovery of new therapeutic targets to prevent and treat heart failure. This potential has been hindered by a lack of rapid and effective methods for analyzing heart size in flies. Here, we demonstrate that analysis of the Drosophila heart with microcomputerized tomography yields accurate and highly reproducible heart size measurements that can be used to analyze heart growth and cardiac hypertrophy in Drosophila.
Collapse
Affiliation(s)
- Courtney E. Petersen
- 1Graduate Program in Molecular and Cell Biology, F. Edward Hébert School of Medicine, Uniformed Services University of the Health Sciences, Bethesda, Maryland
| | - Benjamin A. Tripoli
- 1Graduate Program in Molecular and Cell Biology, F. Edward Hébert School of Medicine, Uniformed Services University of the Health Sciences, Bethesda, Maryland
| | - Todd A. Schoborg
- 2Department of Molecular Biology, University of Wyoming, Laramie, Wyoming
| | - Jeremy T. Smyth
- 3Department of Anatomy, Physiology, and Genetics, F. Edward Hébert School of Medicine, Uniformed Services University of the Health Sciences, Bethesda, Maryland
| |
Collapse
|
4
|
Petersen CE, Wolf MJ, Smyth JT. Suppression of store-operated calcium entry causes dilated cardiomyopathy of the Drosophila heart. Biol Open 2020; 9:bio049999. [PMID: 32086252 PMCID: PMC7075072 DOI: 10.1242/bio.049999] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2019] [Accepted: 02/07/2020] [Indexed: 11/20/2022] Open
Abstract
Store-operated Ca2+ entry (SOCE) is an essential Ca2+ signaling mechanism present in most animal cells. SOCE refers to Ca2+ influx that is activated by depletion of sarco/endoplasmic reticulum (S/ER) Ca2+ stores. The main components of SOCE are STIM and Orai. STIM proteins function as S/ER Ca2+ sensors, and upon S/ER Ca2+ depletion STIM rearranges to S/ER-plasma membrane junctions and activates Orai Ca2+ influx channels. Studies have implicated SOCE in cardiac hypertrophy pathogenesis, but SOCE's role in normal heart physiology remains poorly understood. We therefore analyzed heart-specific SOCE function in Drosophila, a powerful animal model of cardiac physiology. We show that heart-specific suppression of Stim and Orai in larvae and adults resulted in reduced contractility consistent with dilated cardiomyopathy. Myofibers were also highly disorganized in Stim and Orai RNAi hearts, reflecting possible decompensation or upregulated stress signaling. Furthermore, we show that reduced heart function due to SOCE suppression adversely affected animal viability, as heart specific Stim and Orai RNAi animals exhibited significant delays in post-embryonic development and adults died earlier than controls. Collectively, our results demonstrate that SOCE is essential for physiological heart function, and establish Drosophila as an important model for understanding the role of SOCE in cardiac pathophysiology.
Collapse
Affiliation(s)
- Courtney E Petersen
- Graduate Program in Molecular and Cellular Biology, Uniformed Services University of the Health Sciences, F. Edward Hébert School of Medicine, Bethesda, MD 20814, USA
| | - Matthew J Wolf
- Division of Cardiovascular Medicine, Department of Medicine, The University of Virginia School of Medicine, Charlottesville, VA 22908, USA
| | - Jeremy T Smyth
- Department of Anatomy, Physiology, and Genetics, Uniformed Services University of the Health Sciences, F. Edward Hébert School of Medicine, Bethesda, MD 20814, USA
| |
Collapse
|
5
|
Abstract
Previous evidence suggests multiple anesthetic binding sites on human serum albumin, but to date, we have only identified Trp-214 in an interdomain cleft as contributing to a binding site. We used a combination of site-directed mutagenesis, photoaffinity labeling, amide hydrogen exchange, and tryptophan fluorescence spectroscopy to evaluate the importance to binding of a large domain III cavity and compare it to binding character of the 214 interdomain cleft. The data show anesthetic binding in this domain III cavity of similar character to the interdomain cleft, but selectivity for different classes of anesthetics exists. Occupancy of these sites stabilizes the native conformation of human serum albumin. The features necessary for binding in the cleft appear to be fairly degenerate, but in addition to hydrophobicity, there is evidence for the importance of polarity. Finally, myristate isosterically competes with anesthetic binding in the domain III cavity and allosterically enhances anesthetic binding in the interdomain cleft.
Collapse
Affiliation(s)
- R G Eckenhoff
- Department of Anesthesia, University of Pennsylvania Medical Center, Philadelphia, Pennsylvania 19104-4283, USA.
| | | | | | | |
Collapse
|
6
|
Abstract
Site-directed mutagenesis of human serum albumin was used to study the role of various amino acid residues in bilirubin binding. A comparison of thermodynamic, proteolytic, and x-ray crystallographic data from previous studies allowed a small number of amino acid residues in subdomain 2A to be selected as targets for substitution. The following recombinant human serum albumin species were synthesized in the yeast species Pichia pastoris: K195M, K199M, F211V, W214L, R218M, R222M, H242V, R257M, and wild type human serum albumin. The affinity of bilirubin was measured by two independent methods and found to be similar for all human serum albumin species. Examination of the absorption and circular dichroism spectra of bilirubin bound to its high affinity site revealed dramatic differences between the conformations of bilirubin bound to the above human serum albumin species. The absorption and circular dichroism spectra of bilirubin bound to the above human serum albumin species in aqueous solutions saturated with chloroform were also examined. The effect of certain amino acid substitutions on the conformation of bound bilirubin was altered by the addition of chloroform. In total, the present study suggests a dynamic, unusually flexible high affinity binding site for bilirubin on human serum albumin.
Collapse
Affiliation(s)
- C E Petersen
- Department of Biochemistry and Biophysics, John A. Burns School of Medicine, University of Hawaii, Honolulu, Hawaii 96822, USA
| | | | | | | | | |
Collapse
|
7
|
Jarman KH, Cebula ST, Saenz AJ, Petersen CE, Valentine NB, Kingsley MT, Wahl KL. An algorithm for automated bacterial identification using matrix-assisted laser desorption/ionization mass spectrometry. Anal Chem 2000; 72:1217-23. [PMID: 10740862 DOI: 10.1021/ac990832j] [Citation(s) in RCA: 165] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
An algorithm for bacterial identification using matrix-assisted laser desorption/ionization (MALDI) mass spectrometry is being developed. This mass spectral fingerprint comparison algorithm is fully automated and statistically based, providing objective analysis of samples to be identified. Based on extraction of reference fingerprint ions from test spectra, this approach should lend itself well to real-world applications where samples are likely to be impure. This algorithm is illustrated using a blind study. In the study, MALDI-MS fingerprints for Bacillus atrophaeus ATCC 49337, Bacillus cereus ATCC 14579T, Escherichia coli ATCC 33694, Pantoea agglomerans ATCC 33243, and Pseudomonas putida F1 are collected and form a reference library. The identification of test samples containing one or more reference bacteria, potentially mixed with one species not in the library (Shewanella alga BrY), is performed by comparison to the reference library with a calculated degree of association. Out of 60 samples, no false positives are present, and the correct identification rate is 75%. Missed identifications are largely due to a weak B. cereus signal in the bacterial mixtures. Potential modifications to the algorithm are presented and result in a higher than 90% correct identification rate for the blind study data, suggesting that this approach has the potential for reliable and accurate automated data analysis of MALDI-MS.
Collapse
Affiliation(s)
- K H Jarman
- Pacific Northwest National Laboratory, Richland, Washington 99352, USA
| | | | | | | | | | | | | |
Collapse
|
8
|
Ha CE, Petersen CE, Park DS, Harohalli K, Bhagavan NV. Investigations of the effects of ethanol on warfarin binding to human serum albumin. J Biomed Sci 2000; 7:114-21. [PMID: 10754385 DOI: 10.1007/bf02256617] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022] Open
Abstract
Ethanol effects on warfarin binding to human serum albumin (HSA) have been studied by equilibrium dialysis and fluorescence methods at pH 7.4 in phosphate-buffered saline at 37 degrees C. In the presence of various amounts of ethanol fluorescence intensity of bound warfarin decreased significantly but this intensity reduction was not solely from displacement of bound warfarin from HSA. By comparing fluorescence and equilibrium dialysis data we concluded that fluorescence intensity reduction of warfarin was mainly the result of changes in the surrounding environment of the warfarin binding site by ethanol interaction with HSA and that displacement of bound warfarin was not significant compared to the fluorescence intensity changes. The dissociation constant of warfarin binding to HSA decreased with an increasing amount of ethanol. From the changes in fluorescence intensity upon warfarin binding to HSA with the presence of ethanol ranging from 0 to 5.0% the following dissociation constants (Kd) were determined: 0% ethanol 5.39 +/- 0.2 microM, 0.1% ethanol 5.86 +/- 0.1 microM, 0.3% ethanol 5.83 +/- 0.2 microM, 0.5% ethanol 6.76 +/- 0.1 microM, 1% ethanol 7.01 +/- 0.1 microM, 3% ethanol 9.9 +/- 0.7 microM, 5% ethanol 13.01 +/- 0.1 microM. From the equilibrium dialysis with the same ranges of ethanol presence the following Kd values were obtained: 0% ethanol 6. 62 +/- 1.6 microM, 0.1% ethanol 6.81 +/- 1.1 microM, 0.3% ethanol 8. 26 +/- 2.5 microM, 0.5% ethanol 8.86 +/- 1.9 microM, 1% ethanol 11. 01 +/- 4.2 microM, 3% ethanol 20.75 +/- 2.4 microM, 5% ethanol 21.67 +/- 2.2 microM. The results suggest that warfarin bound to HSA was displaced by ethanol. These data indicate that ethanol influence on warfarin binding to HSA may alter the pharmacokinetics of warfarin.
Collapse
Affiliation(s)
- C E Ha
- Department of Biochemistry and Biophysics, John A. Burns School of Medicine, University of Hawaii, Honolulu, Hawaii 96822, USA
| | | | | | | | | |
Collapse
|
9
|
Abstract
Two distinct genotypes that result in the amino acid substitutions R218P and R218H in subdomain 2A of human serum albumin (HSA) have been identified as the cause of familial dysalbuminemic hyperthyroxinemia (FDH). These substitutions increase the affinity of subdomain 2A for thyroxine by approximately 10-fold elevating plasma thyroxine levels in affected individuals. While many studies have examined the binding of thyroxine to FDH HSA, the binding of FDH HSA to drugs has not been widely investigated. The widely administered drug warfarin was selected as a model compound to study FDH HSA/drug interactions since it binds to subdomain 2A and its pharmacokinetics are dramatically influenced by HSA binding. Using two independent methods, fluorescence spectroscopy and equilibrium dialysis with radioactive warfarin, the binding of recombinant R218P, R218H, R218M and wild type HSA to warfarin was measured. Both methods showed an approximately 5-fold decrease in the affinity of R218P, R218H and R218M HSA for warfarin relative to wild type HSA. The Kd values determined by fluorescence spectroscopy for wild type, R218H, R218P and R218M HSA binding to warfarin were 1.35, 5.38, 5.61, and 8.34 microM, respectively. The values determined by equilibrium dialysis were 5.36, 29.5, 14.5, and 23.4 microM, respectively. Based on the above findings one would expect the free serum warfarin concentration in homozygous R218P and R218H FDH patients to be elevated about 5-fold, resulting in about a 5-fold reduction in the serum half-life of the drug.
Collapse
Affiliation(s)
- C E Petersen
- Department of Biochemistry and Biophysics, John A. Burns School of Medicine, University of Hawaii at Manoa, Honolulu 96822, USA
| | | | | | | | | |
Collapse
|
10
|
Petersen CE, Ha CE, Harohalli K, Park DS, Feix JB, Isozaki O, Bhagavan NV. Structural investigations of a new familial dysalbuminemic hyperthyroxinemia genotype. Clin Chem 1999; 45:1248-54. [PMID: 10430791] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/13/2023]
Abstract
BACKGROUND In a previous study, we found that the amino acid substitution R218H in human serum albumin (HSA) was the cause of familial dysalbuminemic hyperthyroxinemia (FDH) in several Caucasian patients. Subsequently the substitution R218P was shown to be the cause of FDH in several members of a Japanese family. This study attempts to resolve discrepancies in the only other study of R218P HSA and identifies two new Japanese R218P FDH patients unrelated to those described previously. METHODS AND RESULTS Recombinant R218H, R218P, and wild-type HSA were synthesized in yeast, and the affinities of these HSA species for l- and d-thyroxine were determined using fluorescence spectroscopy. The dissociation constants for the binding of wild-type, R218P, and R218H HSA to l-thyroxine were 1.44 x 10(-6), 2.64 x 10(-7), and 2.49 x 10(-7) mol/L, respectively. The circular dichroism spectra of thyroxine bound to R218H and R218P HSA were markedly different, indicating that the structure of the thyroxine/HSA complex is different for either protein. CONCLUSIONS The K(d) values for l-thyroxine bound to R218P and R218H HSA determined in this study were similar. The extremely high serum total-thyroxine concentrations reported previously for R218P FDH patients (10-fold higher than those reported for R218H FDH patients) are not consistent with the K(d) values determined in this study. Possible explanations for these discrepancies are discussed.
Collapse
Affiliation(s)
- C E Petersen
- Department of Biochemistry and Biophysics, University of Hawaii, 1960 East-West Rd., Honolulu, HI 96822, USA
| | | | | | | | | | | | | |
Collapse
|
11
|
Park DS, Petersen CE, Ha C, Harohalli K, Feix JB, Bhagavan NV. Expression of a human serum albumin fragment (consisting of subdomains IA, IB, and IIA) and a study of its properties. IUBMB Life 1999; 48:169-74. [PMID: 10794593 DOI: 10.1080/713803501] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Abstract
Site-directed mutagenesis and a yeast expression system were used to synthesize a human serum albumin (HSA) fragment (amino acids 1-297). The HSA fragment (half HSA) was evaluated with a number of biophysical techniques and found to be similar to the corresponding region in wild-type HSA. Specifically, the circular dichroism spectra of half HSA and wild-type HSA were superimposable, indicating that the highly alpha-helical secondary structure of wild-type HSA is preserved in half HSA. Additionally, half HSA was partially reactive with a polyclonal antibody against authentic HSA. Half HSA, which contains subdomain IIA, had an affinity for thyroxine and several thyroxine analogs, similar to that observed previously for wild-type HSA. This study suggests that the production of recombinant HSA fragments will be useful for the study of HSA ligand interactions.
Collapse
Affiliation(s)
- D S Park
- Department of Biochemistry and Biophysics, John A. Burns School of Medicine, University of Hawaii, Honolulu 96822, USA
| | | | | | | | | | | |
Collapse
|
12
|
Saenz AJ, Petersen CE, Valentine NB, Gantt SL, Jarman KH, Kingsley MT, Wahl KL. Reproducibility of matrix-assisted laser desorption/ionization time-of-flight mass spectrometry for replicate bacterial culture analysis. Rapid Commun Mass Spectrom 1999; 13:1580-1585. [PMID: 10421900 DOI: 10.1002/(sici)1097-0231(19990815)13:15<1580::aid-rcm679>3.0.co;2-v] [Citation(s) in RCA: 67] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOFMS) was used to demonstrate the reproducibility of bacterial spectra collected on different days. The reproducibility of analysis by MALDI-MS of intact Escherichia coli and Bacillus atrophaeus is presented as a replicate culture study in which spectra were collected on ten different occasions over a three-month period and by two different operators. The analysis resulted in the detection of specific biomarkers in the m/z 2000-20 000 range. Some of the peaks in the Escherichia coli spectra are identified by comparison with other published work. All of the spectra obtained are reproducible over the course of the experiment, but operator variability does exist. The Escherichia coli spectra show operator variability while the Bacillus atrophaeus spectra do not. This work demonstrates the utility of MALDI in obtaining consistent spectra from bacteria over a period of time.
Collapse
Affiliation(s)
- A J Saenz
- Battelle Pacific Northwest National Laboratory, Richland, WA 99352, USA
| | | | | | | | | | | | | |
Collapse
|
13
|
Jarman KH, Daly DS, Petersen CE, Saenz AJ, Valentine NB, Wahl KL. Extracting and visualizing matrix-assisted laser desorption/ionization time-of-flight mass spectral fingerprints. Rapid Commun Mass Spectrom 1999; 13:1586-1594. [PMID: 10421901 DOI: 10.1002/(sici)1097-0231(19990815)13:15<1586::aid-rcm680>3.0.co;2-2] [Citation(s) in RCA: 43] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
We have developed a method for constructing and extracting matrix-assisted laser desorption/ionization (MALDI) fingerprints. This method is fully automated and statistically based, allowing a large number of spectra to be analyzed at a time in an objective manner. This method can be used to extract the fingerprint of a particular analyte from a spectrum containing multiple analytes. Therefore, this method lends itself well to real-world applications where samples to be analyzed are likely to be impure. We illustrate this method on experimental results from a series of studies of E. coli and B. atrophaeus MALDI time-of-flight mass spectrometry (TOFMS) fingerprints.
Collapse
Affiliation(s)
- K H Jarman
- Pacific Northwest National Laboratory, Richland, WA 99352, USA
| | | | | | | | | | | |
Collapse
|
14
|
Petersen CE, Ha CE, Harohalli K, Park D, Bhagavan NV. Mutagenesis studies of thyroxine binding to human serum albumin define an important structural characteristic of subdomain 2A. Biochemistry 1997; 36:7012-7. [PMID: 9188698 DOI: 10.1021/bi970225v] [Citation(s) in RCA: 41] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
The familial dysalbuminemic hyperthyroxinemia (FDH) phenotype results from a natural human serum albumin (HSA) mutant, with histidine instead of arginine at amino acid position 218. This mutation results in an enhanced affinity for thyroxine. In our earlier study, site-directed mutagenesis and a yeast protein expression system were used to synthesize FDH HSA and several other HSA mutants. Measurement of the binding of these HSA mutants to thyroxine and several thyroxine analogs using equilibrium dialysis and quenching of tryptophan 214 fluorescence allowed us to propose a preliminary model of thyroxine binding to the 2A subdomain of wild type and FDH HSA. In this study, we have produced several other HSA mutants. By comparing the binding affinity of these mutants for thyroxine and tetraiodothyroacetic acid to the binding affinity of other mutants, we were able to suggest a new model for thyroxine binding to the 2A subdomain of HSA. We found that the substitution of arginine at position 218 with alanine increased the binding affinity for thyroxine by 2 orders of magnitude relative to the binding affinity of wild type HSA for thyroxine. A more accurate understanding of the mechanism of thyroxine binding to HSA has allowed us to define an important structural characteristic of subdomain 2A, one of the two principal binding sites on HSA for small hydrophobic ligands.
Collapse
Affiliation(s)
- C E Petersen
- Department of Biochemistry and Biophysics, University of Hawaii, Honolulu 96822, USA
| | | | | | | | | |
Collapse
|
15
|
Abstract
Human serum albumin (HSA) contains a single tryptophan residue at position 214. The emission properties of tryptophan 214 from recombinant albumins, namely, normal HSA, FDH-HSA and a methionine 218 HSA were examined. In all cases, the excited state lifetimes were best described by a two component model consisting mainly of a Lorentzian distribution. The centers of these distributions were 5.60 ns for HSA, 4.23 ns for FDH-HSA, and 6.08 ns for Met-218 HSA. The global rotational correlation times of the three HSAs were near 41 ns while the amplitude and rate of the local motion varied. These changes in the lifetimes and mobilities suggest perturbation in the local protein environment near tryptophan 214 as a consequence of the amino acid substitutions.
Collapse
Affiliation(s)
- M K Helms
- Department of Biochemistry and Biophysics, University of Hawaii at Manoa, Honolulu 96822, USA
| | | | | | | |
Collapse
|
16
|
Petersen CE, Ha CE, Jameson DM, Bhagavan NV. Mutations in a specific human serum albumin thyroxine binding site define the structural basis of familial dysalbuminemic hyperthyroxinemia. J Biol Chem 1996; 271:19110-7. [PMID: 8702585 DOI: 10.1074/jbc.271.32.19110] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023] Open
Abstract
The familial dysalbuminemic hyperthyroxinemia (FDH) phenotype results from a natural human serum albumin (HSA) mutant with histidine instead of arginine at amino acid position 218. This mutation results in an enhanced affinity for thyroxine. Site-directed mutagenesis and a yeast protein expression system were used to synthesize wild type HSA and FDH HSA as well as several other HSA mutants. Studies on the binding of thyroxine to these HSA species using equilibrium dialysis and quenching of tryptophan 214 fluorescence suggest that the FDH mutation affects a single thyroxine binding site located in the 2A subdomain of HSA. Site-directed mutagenesis of HSA and thyroxine analogs were used to obtain information about the mechanism of thyroxine binding to both wild type and FDH HSA. These studies suggest that the guanidino group of arginine at amino acid position 218 in wild type HSA is involved in an unfavorable binding interaction with the amino group of thyroxine, whereas histidine at amino acid position 218 in FDH HSA is involved in a favorable binding interaction with thyroxine. Neither arginine at amino acid position 222 nor tryptophan at amino acid position 214 appears to favorably influence the binding of thyroxine to wild type HSA.
Collapse
Affiliation(s)
- C E Petersen
- Department of Biochemistry and Biophysics, University of Hawaii, Honolulu, Hawaii 96822, USA
| | | | | | | |
Collapse
|
17
|
Abstract
In this study a protein expression system was used to synthesize recombinant human serum albumin containing a mutation that has been shown to result in familial dysalbuminemic hyperthyroxinemia. Equilibrium dialysis was used to measure the binding of this recombinant human serum albumin with thyroxine. The association constant determined for the binding of this human serum albumin variant with thyroxine was shown to be 65-fold greater than that of recombinant normal human serum albumin.
Collapse
Affiliation(s)
- C E Petersen
- Department of Biochemistry and Biophysics, John A. Burns School of Medicine, University of Hawaii, Honolulu, USA
| | | | | | | |
Collapse
|
18
|
Petersen CE, Scottolini AG, Cody LR, Mandel M, Reimer N, Bhagavan NV. A point mutation in the human serum albumin gene results in familial dysalbuminaemic hyperthyroxinaemia. J Med Genet 1994; 31:355-9. [PMID: 8064810 PMCID: PMC1049864 DOI: 10.1136/jmg.31.5.355] [Citation(s) in RCA: 62] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
Using DNA samples obtained from two unrelated patients, diagnosed as having familial dysalbuminaemic hyperthyroxinaemia (FDH), exons 1-14 which span the entire coding region of the human serum albumin (HSA) gene were amplified by the polymerase chain reaction. The sequence of each of the 14 DNA fragments was then determined. In each case a point mutation was identified at nucleotide 653 which causes an Arg to His substitution at amino acid position 218. The substitution was confirmed by amino acid sequencing of a mutant peptide resulting from tryptic digestion of the protein. Abnormal affinity of FDH HSA for a thyroxine (T4) analogue was verified by an adaptation of the procedure used in routine free T4 measurement. The location of the mutation is discussed in relation to other studies on the binding properties of HSA.
Collapse
Affiliation(s)
- C E Petersen
- Department of Biochemistry and Biophysics, John A Burns School of Medicine, University of Hawaii, Honolulu 96822
| | | | | | | | | | | |
Collapse
|
19
|
Abstract
Iodide-induced hypothyroidism with high TSH and low T4 under long term potassium iodide medication was observed in a toddler suffering from chronic wheezy bronchitis -- in spite of intermittent application. The pathophysiology of iodide-induced hypothyroidism and the apparent immaturity of adaptation to high exogenous iodide in newborn and infants are discussed.
Collapse
|
20
|
Christen HJ, Aksu F, Petersen CE. [Isolated abducent nerve paralysis in infectious mononucleosis]. Monatsschr Kinderheilkd 1983; 131:532-4. [PMID: 6633545] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
Infectious mononucleosis in children and adolescents is characterized by a large variability of symptoms and clinical course. Serological tests for Epstein-Barr-Virusspecific antibodies are a valuable aid in differential diagnosis, in particular for pediatricians. - Isolated palsy of the abducens nerve is reported in a 12-year-old girl. The parainfectious etiology of this mononeuritis was determined only by specific serological tests.
Collapse
|
21
|
Abstract
The relationships between the size of the articular surface of the mandibular condyle and masticatory muscle size, tooth size, diet, and biomechanical variables associated with mastication were studied by taking 12 measurements on skulls of 253 adult female anthropoid primates, including three to ten specimens from each of 32 species. In regressions of condylar length, width, or area against body weight, logarithmic transformations substantially improve the fit of the equations compared with untransformed data. There is a strong relationship between condylar measurements and body weight, with all correlations being .94 or higher. The slopes of the allometric regressions of length, width, and area of the condylar head indicate slight positive allometry with body size. Folivorous primates have smaller condyles than frugivorous primates, and colobines have smaller condyles than cebids, cercopithecines, or hominoids. When colobines are eliminated, the differences between frugivores and folivores are not significant. However, the two species with the relatively largest condyles are Pongo pygmaeus and Cercocebus torquatus, suggesting that there may be a relationship between unusually large condylar dimensions and the ability to crack hard nuts between the teeth. Cranial features having strong positive correlations with condylar dimensions include facial prognathism, maxillary incisor size, maxillary postcanine area, mandibular ramus breadth, and temporal fossa area. These data are interpreted as indicating that relatively large condyles are associated with relatively large masticatory muscles, relatively inefficient mandibular biomechanics, and a large dentition. These relationships support the growing evidence that the temporomandibular joint is a stress-bearing joint in normal function.
Collapse
|
22
|
Mabeck CE, Albertsen J, Andersen K, Andersen NN, Elmer M, Faber-Hansen K, Fallow J, Gauguin J, Hansen JH, Jensen F, Jensen JP, Larsen P, Lolk J, Moller B, Petersen CE, Schiottz-Christensen E, Trautner M, Vinten A, Werlinrud K. [Notification of occupational diseases in general practice. Patient acceptance of notification]. Ugeskr Laeger 1976; 138:1540-2. [PMID: 936320] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
|
23
|
Petersen CE, Bräutigam N, Uthgenannt H, Zwad HD. [Brain scintigraphic findings in children with meningoencephalitis]. Monatsschr Kinderheilkd (1902) 1974; 122:435-6. [PMID: 4408703] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
|
24
|
Doose H, Gerken H, Petersen CE, Völzke E. Electroencephalographic investigations on the genetics of infantile centrencephalic epilepsies. Electroencephalogr Clin Neurophysiol 1969; 26:444. [PMID: 4183603] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
|
25
|
Petersen CE, Doose H. Serial EEG studies in centrencephalic epilepsy in children born prematurely. Electroencephalogr Clin Neurophysiol 1969; 26:446. [PMID: 4183610] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
|
26
|
Astrup P, Pauli HG, Kjeldsen K, Petersen CE. Introduction and general description of the study and of the procedures for prolonged exposure to carbon monoxide and hypoxia. Scand J Clin Lab Invest Suppl 1968; 103:5-8. [PMID: 5720770] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
|
27
|
Doose H, Gerken H, Petersen CE, Völzke E. [Electroencephalographic studies on the genetics of spasmophilia of the centrencephalic type]. Med Welt 1967; 8:417-21. [PMID: 6044560] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
|
28
|
Doose H, Petersen CE. [On the diagnostic value of single EEG-recordings in childhood. (On the method of a statistical adaptation of EEG-findings)]. Nervenarzt 1966; 37:513-5. [PMID: 5983179] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
|
29
|
Doose H, Petersen CE, Völzke E, Herzberger E. [Fever cramps and epilepsy. I. Etiology, clinical picture and course of the so-called infection or fever cramps]. Arch Psychiatr Nervenkr (1970) 1966; 208:400-12. [PMID: 5969588 DOI: 10.1007/bf00343054] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
|
30
|
Doose H, Völzke E, Petersen CE, Herzberger E. [Fever cramps and epilepsy. II. Electroencephalographic study of the course of so-called fever or infection cramps]. Arch Psychiatr Nervenkr (1970) 1966; 208:413-32. [PMID: 5969589 DOI: 10.1007/bf00346164] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
|