Potential of ion mobility mass spectrometry in cellulose ether analysis: substitution pattern of hydroxyethyl celluloses.

Ion mobility mass spectrometry (ESI-tims-ToF-MS, syringe pump infusion) has been applied to glucose and oligosaccharide ethers derived from hydroxyethyl-methyl celluloses (HEMC) and hydroxyethyl celluloses (HEC) after permethylation and partial depolymerization: by hydrolysis without or with subsequent reductive amination with m-amino benzoic acid (mABA) or by reductive cleavage. As model compounds without tandem substitution methoxyethylated methylcellulose was used. Regioisomeric glucose ethers were separated according to their ion mobility, and positions of substitution could be assigned.

Comparing C methyl and deuterated methyl isotopic labeling for the quantification of methyl cellulose patterns using mass spectrometry.

The methyl substitution along and among the polymer chains of methyl cellulose (MC) is commonly analyzed by ESI-MS after perdeuteromethylation of the free-OH groups and partial hydrolysis to cello-oligosaccharides (COS). This method requires a correct quantification of the molar ratios of the constituents belonging to a particular degree of polymerization (DP). However, isotopic effects are most pronounced for H/D since their mass difference is 100%.

The MITOCHONDRIAL TRANSCRIPT STABILITY FACTOR 4 (MTSF4) is essential for the accumulation of dicistronic rpl5-cob mRNAs in Arabidopsis thaliana.

The Arabidopsis thaliana genome harbors more than 450 nuclear genes encoding pentatricopeptide repeat (PPR) proteins that operate in the RNA metabolism of mitochondria and/or plastids. To date, the molecular function of many PPR proteins is still unknown. Here we analyzed the nucleus-encoded gene At4g19440 coding for a P-type PPR protein.

Impact of instrumental settings in electrospray ionization ion trap mass spectrometry on the analysis of O-methoxyethyl-O-methyl cellulose: a comprehensive quantitative evaluation.

The hydroxyethyl substitution along and among the polymer chains of respective cellulose ethers (HEC and HEMC) can be analyzed by ESI-IT-MS after permethylation of the free OH-groups, partial hydrolysis, and mABA labeling. This method requires the correct quantification of the molar ratios of the constituents belonging to a particular degree of polymerization (DP) with respect to their numbers of MeOEt and Me groups without any discrimination along the MS analysis pathway. The influence of the chemistry on the ionization and the impact of the voltages controlling the ion transport (Cap Exit, Octopoles) and the ion storage efficiency (Trap Drive, TD) on a relative quantification were studied using binary equimolar mixtures of cellobiose with increasing number of methoxyethyl and decreasing number of methyl groups (Δ m/z 88, 2× MeOEt).

Impact of instrumental settings in electrospray ionization ion trap mass spectrometry on the analysis of multi-CH-/CD-isotopologs in cellulose ether analysis: a quantitative evaluation.

Exact quantification of the molar ratios of isotopologous mixed O-methyl-O-methyl-d-cellooligosaccharides (COS) comprising all combinations from fully methylated to fully deuteromethylated constituents within an individual degree of polymerization (DP) is the key step in the analysis of the substituent distribution over the polymer chains in methyl celluloses (MC). Deuteromethylation of MC is performed to level chemical differences, but due to a m/z range of 3 DP·ΔMe/Me-d, bias during MS measurement cannot certainly be excluded. Therefore, ionization, ion transportation, and ion storage were studied with an electrospray ionization ion trap mass spectrometer (ESI-IT-MS) using binary equimolar mixtures of per-O-Me- and per-O-Me-d-COS, defining the border cases of a particular Me/Me-d-profile.

In Arabidopsis thaliana mitochondria 5' end polymorphisms of nad4L-atp4 and nad3-rps12 transcripts are linked to RNA PROCESSING FACTORs 1 and 8.

RNA PROCESSING FACTORs 1 AND 8 (RPF1 and RPF8), both restorer of fertility like pentatricopeptide repeat proteins, are required for processing of dicistronic nad4L-atp4 and nad3-rps12 transcripts in Arabidopsis mitochondria. In mitochondria of Arabidopsis thaliana (Arabidopsis), the 5' termini of many RNAs are generated on the post-transcriptional level. This process is still poorly understood in terms of both the underlying mechanism as well as proteins required.

In Arabidopsis thaliana distinct alleles encoding mitochondrial RNA PROCESSING FACTOR 4 support the generation of additional 5' termini of ccmB transcripts.

In plant mitochondria, the 5' ends of many transcripts are generated post-transcriptionally. We show that the pentatricopeptide repeat (PPR) protein RNA PROCESSING FACTOR 4 (RPF4) supports the generation of extra 5' ends of ccmB transcripts in Landsberg erecta (Ler) and a number of other Arabidopsis thaliana ecotypes. RPF4 was identified in Ler applying a forward genetic approach supported by complementation studies of ecotype Columbia (Col), which generates the Ler-type extra ccmB 5' termini only after the introduction of the RPF4 allele from Ler.