Molecular mass calculation

A cDNA encoding apoobelin was obtained from O. longissima and sequenced (Illarionov et al., 1995). The deduced amino acid sequence of the apoobelin consists of 195 amino acid residues, with a calculated molecular mass of about 22.2 kDa, closely matching the apoproteins of other Ca2+-sensitive photoproteins such as aequorin from the jellyfish Aequorea (Inouye et al., 1985 Prasher et al., 1985) and clytin from the jellyfish Phialidium gregarium (Inouye and Tsuji, 1993). To obtain recombinant apoobelin, the cDNA encoding apoobelin was expressed in E. coli (Illarionov et al., 2000). The recombinant apoobelin produced was purified and converted into obelin by incubation with coelenterazine in the presence of molecular oxygen and 2-mercaptoethanol or dithioerythritol, as in the case of aequorin. 

The effective molecular mass Mc of the network strands was determined experimentally from the moduli of the polymers at temperatures above the glass transition (Sect. 3) [11]. lVlc was derived from the theory of rubber elasticity. Mc and the calculated molecular mass MR (Eq. 2.1) of the polymers A to D are compared in Table 3.1. 

The outlined scheme can also be used to calculate the amount of phosphoric acid triesters. In that case the difference must be formed of the total phosphorus content minus that of free phosphoric acid, phosphoric acid monoester, and phosphoric acid diester. The resulting value is then multiplied with the calculated molecular mass of the triester. 

The pecM gene encodes a protein of 297 amino acids with a calculated molecular mass of 32 kDa. The predicted PecM protein displays the characteristics of an integral membrane protein since it is largely hydrophobic, with potential trans-membrane domains. SubceUular firactionation confirmed that PecM is anchored into the bacterial inner membrane whereas PecS is... 

Explain how the following errors would affect the calculated molecular mass ... 

For ohgosaccharide size, the detected masses are compared to calculated molecular masses of variable ohgosaccharide moieties to determine the monosaccharide residues that are lacking in each patient (Fig. 4.5.9). 

Molecular size greatly affects transport across cellular membranes. As molecular size increases, transport across membranes decreases, because increases in molecular size will increase "frictional resistance" and decrease the diffusivity through the cell membrane. Since molecular size is generally directly proportional to molecular mass, and molecular mass is easily calculated molecular mass is often used as a descriptor of molecular size. Hence, as a general rule, the lower the molecular mass, the smaller are the molecules composing the substance, and the more easily the substance can cross membranes and be absorbed from the gastrointestinal tract, lung, and skin. 

The genomic DNA encoding Prl in the other main insect pathogenic Beauveria species, B. brongniartii contains three introns that are 64, 57-, and 61-bp long (Sheng et al., 2006). The deduced amino-acid sequence of the protein shows similarity to that of Prl from M anisopliae (67%), and Prl from B. bassiana (76%). The calculated molecular mass of the Prl precursor is 39121 Da and its pi is 8.0. The protein has three active sites characteristic of subtilisin-like serine proteases. 

For example, ESI/MS allowed the analysis of various proteins derived from the HIV virus and obtained by genetic engineering, such as the pl8 protein [116]. Beyond the main peak series corresponding to the protein with a measured molecular mass of 14 590 Da (as opposed to a calculated molecular mass of 14 589 Da), the spectrum shown in Figure 8.20 contains two other series. The first minor series (8 %) indicated by the letter T and giving a measured mass of 12651 Da corresponds to the C-terminal side of pl8 cleaved at position 111-112, whereas the second series (3 %) indicated by the letter D with a measured mass of 29 175 Da corresponds to the dimer formed by the linkage of two cysteines of two different proteins. 

Calculated molecular masses are based on average molecular weight for the individual amino acids. 

The mung bean (Vigna radiata, Wilczek) sucrose synthase is a tetramer composed of identical subunits of 95 kDa, and its cDNA contains an open reading frame of 2,415 bp that encodes a polypeptide of 805 amino adds with a calculated molecular mass of 92,087 daltons. The recombinant sucrose synthase expressed... 

Based on a sequence of 148 amino acid residues, calmodulin has a calculated molecular mass of 16,800, which lies about midway in a series of reported values determined by sedimentation... 

A fragment of the lettuce VDE cDNA was amplified from lettuce cDNA by PCR and used to isolate a near full-length cDNA for lettuce VDE (Bugos and Yamamoto, 1996). The cDNA encoded a polypeptide of 473 amino acids with a calculated molecular mass of 54.4 kDa. This was confirmed from in vitro transcription/translation of the VDE cDNA which produced a 55 kDa polypeptide when analyzed by SDS-PAGE. The deduced preprotein contained a 125 amino acid bipartite transit peptide for transport into the chloroplast and thylakoid lumen. Based on the N-terminal sequence of the purified VDE from lettuce, which indicates the transit peptide cleavage site, the mature VDE protein is encoded by 348 amino acids with a calculated molecular mass of... 

The gene encodes for a secreted protein, with the mature protein possessing 119 amino acids. The calculated molecular mass and isoelectric point of the recombinant form are very similar to those obtained by electrophoretic methods on the purified protein (Barde et al., 1982). A striking feature of the primary structure of mature BDNF is its similarity to NGF. There are 51 amino acids common to the various NGF s and to BDNF, including all six cysteine residues (Leibrock et al.,... 

Analysis of the protein content of active fractions revealed two bands in the fraction eluted by urea (Fig, 1 A). The apparent molecular masses of the proteins, 90 and 70 kDa, corresponded well to the molecular masses calculated from the deduced amino acid sequences of GyrA (90,460 kDa) and GyrB (72,459 Da). The concentration of DNA gyrase (GyrA and GyrB) in fractions was estimated to be 40 ng/jjtl, i.e., about 120 nM with a calculated molecular mass of 325,838 Da for the heterotetramer A2B2. 

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