scholarly journals Membrane Binding Properties and Terminal Residues of the Mature Hepatitis C Virus Capsid Protein in Insect Cells

2004 ◽  
Vol 78 (21) ◽  
pp. 11766-11777 ◽  
Author(s):  
Tomoaki Ogino ◽  
Hiroyuki Fukuda ◽  
Shinobu Imajoh-Ohmi ◽  
Michinori Kohara ◽  
Akio Nomoto
Keyword(s):  
Hepatitis C Virus ◽  
Hepatitis C ◽  
Molecular Mass ◽  
Posttranslational Modifications ◽  
Core Protein ◽  
Membrane Binding ◽  
Binding Properties ◽  
Maldi Tof Ms ◽  
Maldi Tof ◽  
Tof Ms

ABSTRACT The immature core protein (p23, residues 1 to 191) of hepatitis C virus undergoes posttranslational modifications including intramembranous proteolysis within its C-terminal signal sequence by signal peptide peptidase to generate the mature form (p21). In this study, we analyzed the cleavage site and other amino acid modifications that occur on the core protein. To produce the posttranslationally modified core protein, we used a baculovirus-insect cell expression model system. As previously reported, p23 is processed to form p21 in insect as well as in mammalian cells. p21 was found to be associated with the cytoplasmic membrane, and its significant portion behaved as an integral membrane protein. The protein was purified from the membrane by a simple and unique procedure on the basis of its membrane-binding properties and solubility in detergents. Matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS) analysis of purified p21 showed that the average molecular mass (m/z 19,307) of its single-charged ion differs by m/z 1,457 from that calculated for p23. To determine the posttranslational modifications, tryptic p21 peptides were analyzed by MALDI-TOF MS. We found three peptides that did not match the theoretically derived peptides of p23. Analysis of these peptides by MALDI-TOF tandem MS revealed that they correspond to N-terminal peptides (residues 2 to 9 and 2 to 10) starting with α-N-acetylserine and C-terminal peptide (residues 150 to 177) ending with phenylalanine. These results suggest that the mature core protein (molecular mass of 19,306 Da) includes residues 2 to 177 and that its N terminus is blocked with an acetyl group.

Copper binding properties of a tau peptide associated with Alzheimer's disease studied by CD, NMR, and MALDI-TOF MS

Peptides ◽  
2006 ◽  
Vol 27 (4) ◽  
pp. 841-849 ◽  
Author(s):  
Qingfeng Ma ◽  
Yanmei Li ◽  
Jintang Du ◽  
Huadong Liu ◽  
Kenji Kanazawa ◽  
...  
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Copper Binding ◽  
Binding Properties ◽  
Maldi Tof Ms ◽  
Maldi Tof ◽  
Tof Ms

Direct detection of intact Klebsiella pneumoniae carbapenemases produced by Enterobacterales using MALDI-TOF MS

2020 ◽  
Vol 75 (5) ◽  
pp. 1174-1181 ◽  
Author(s):  
Eun-Jeong Yoon ◽  
Eun Hee Lee ◽  
Dong Hwi Hwang ◽  
Hyukmin Lee ◽  
Je-Hyun Baek ◽  
...  
Keyword(s):  
Molecular Mass ◽  
Sensitivity And Specificity ◽  
Direct Detection ◽  
External Validation ◽  
Agar Plate ◽  
Analytical Sensitivity ◽  
Exact Mass ◽  
Maldi Tof Ms ◽  
Maldi Tof ◽  
Tof Ms

Abstract Objectives A MALDI-TOF MS-based identification method for KPC-producing Enterobacterales was developed. Methods The molecular mass of the intact KPC-2 polypeptide was estimated for blaKPC-2 transformants using MALDI Microflex and the exact mass was confirmed by LC and a high-resolution MS/MS system. A total of 1181 clinical Enterobacterales strains, including 369 KPC producers and 812 KPC non-producers, were used to set up the methodology and the results were compared with those from PCR analyses. For external validation, a total of 458 Enterobacterales clinical isolates from a general hospital between December 2018 and April 2019 were used. Results The exact molecular mass of the intact KPC-2 protein was 28 718.13 Da and KPC peaks were observed at m/z 28 708.87–28 728.34 using MALDI Microflex. Most of the KPC-2 (99.1%, 335/338) and KPC-3 (100%, 6/6) producers presented a clear peak via this method, while 12.0% (3/25) of the KPC-4 producers had a peak of weak intensity associated with low levels of gene expression. It took less than 20 min for the entire assay to be performed with colonies on an agar plate. External validation showed that the analytical sensitivity and specificity of the method compared with PCR were 100% (59/59) and 99.50% (397/399), respectively. Conclusions The MALDI-TOF MS-based method for directly detecting the intact KPC protein is applicable to routine tests in clinical microbiology laboratories, supported by its speed, low cost and excellent sensitivity and specificity.

Optimization for Determination of PolypeptidesRelative Molecular Mass by MALDI-TOF MS

Daxue Huaxue ◽  
2015 ◽  
Vol 30 (5) ◽  
pp. 39-44
Author(s):  
Yu Huijuan ◽  
◽  
◽  
Chu Yuehuan ◽  
Shao Guang ◽  
...  
Keyword(s):  
Molecular Mass ◽  
Maldi Tof Ms ◽  
Maldi Tof ◽  
Tof Ms

scholarly journals Analysis of Minor Hemoglobins by Matrix-Assisted Laser Desorption/Ionization Time-of-Flight Mass Spectrometry

2005 ◽  
Vol 51 (6) ◽  
pp. 989-996 ◽  
Author(s):  
Karin Zurbriggen ◽  
Markus Schmugge ◽  
Marlis Schmid ◽  
Silke Durka ◽  
Peter Kleinert ◽  
...  
Keyword(s):  
Posttranslational Modifications ◽  
Laser Desorption ◽  
Laser Desorption Ionization ◽  
Ionization Time ◽  
Maldi Tof Ms ◽  
Maldi Tof ◽  
Globin Chains ◽  
Flight Mass Spectrometry ◽  
Tof Ms ◽  
Matrix Assisted Laser

Abstract Background: Hemoglobin (Hb) heterogeneity arises mainly from posttranslational modifications of the globin chains, and cation-exchange chromatography reveals falsely increased concentrations of some minor Hbs in the presence of abnormal Hbs. Here we describe a method for identification of the globin chains and their posttranslational modifications contained in the Hb fractions. Methods: We used cation-exchange HPLC (PolyCAT A column) for separation of Hb fractions and matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) for analysis of the separated globin chains. Globin chains were identified by their molecular masses. Posttranslational modifications of globin chains were identified by digestion of the proteins with endoproteinase V8 before MALDI-TOF MS of the resulting peptides. Results: Analysis of the HbA2 fractions of patients with HbS revealed 4 different globin chains. We found, in addition to the expected α- and δ-chains, the carbamylated α- and the βS-chains. Additionally, we analyzed HbH, Hb Barts, HbA1b, pre-HbA1c, HbA1c, HbF1, HbF, HbA1d3a, HbA1d3b, HbA2, and HbC1 fractions from control and pathologic blood samples. We identified several posttranslational modifications of the globin chains, such as pyruvatization, glycation, acetylation, carbamylation, and acetaldehyde adduct formation. Conclusions: The native and posttranslationally modified globin chains in minor and major Hbs are unambiguously identified by MALDI-TOF MS. A minor Hb containing the carbamylated α- and the βS-chain elutes at the same time as normal HbA2 (α2δ2) and thus leads to falsely increased HbA2 values in patients with HbS when blood is analyzed with PolyCAT A chromatography.

Comparison of molecular mass data of biomolecules obtained by GEMMA and MALDI-TOF-MS

1997 ◽  
Vol 28 ◽  
pp. S141-S142 ◽  
Author(s):  
W.W. Szymanski ◽  
S.L. Kaufman ◽  
K. Linnemayr ◽  
G. Allmaier
Keyword(s):  
Molecular Mass ◽  
Maldi Tof Ms ◽  
Mass Data ◽  
Maldi Tof ◽  
Tof Ms
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