Inclusion aggregate formation

Formation of aggregates, which allows inclusion of particulate organic matter (POM), thereby making it inaccessible to decomposing microorganisms, is a fundamental process in C sequestration. Besides the action of the soil macrofauna (already mentioned in Section 5.2), which aids in aggregate formation by reducing the size... 

Georgiou, G. and Bowden, G.A. (1991). Inclusion body formation and the recovery of aggregated recombinant proteins. In Recombinant DNA Technology and Applications. A.Prokop, R.K.Bajpai, and C.Ho, eds. (New York McGraw-Hill), pp. 333 356. 

The problem of in vitro protein folding has become a major barrier to the successful use of bacterial systems for protein production. Bacterial hosts often produce inactive protein in the form of inclusion bodies. The refolding of this inactive protein results in the recovery of the native molecules as well as misfolded and aggregated proteins. Aggregate formation reduces the yield of... 

This book attempts to bridge the gap between fundamental and applied studies on protein folding. Some of the issues addressed include in vivo protein folding, protein aggregation and inclusion body formation, elucidation of the folding pathway, characterization of folding intermediates, and practical considerations in protein renaturation. 

The use of . coli as an expression system is limited to those proteins where post-transla-tional modification such as the glycosylation or galactosylation of antibody fragments is not required. Inclusion body formation can be another disadvantage that occurs with this prokaryotic model, as these insoluble protein aggregates demand laborious and cost-intensive in vitro refolding (denatura-tion and renaturation) and purification steps. 

Although the micellar solubilization can be demonstrated in vitro there is no warrant for a corresponding enhancement of bioavailability by the oral route in any case. With particular combinations of drug substance and surfactant, even reduced instead of improved bioavailability has been observed. Such effects depend on the concentration of the surfactant and may have various reasons such as shift of equilibrium in favour of micellar inclusion or formation of other types of drug-surfactant aggregates. 

The methods involved in the production of proteins in microbes are those of gene expression. Several plasmids for expression of proteins having affinity tails at the C- or N-terminus of the protein have been developed. These tails are usefiil in the isolation of recombinant proteins. Most of these vectors are commercially available along with the reagents that are necessary for protein purification. A majority of recombinant proteins that have been attempted have been produced in E. Coli (1). In most cases these recombinant proteins formed aggregates resulting in the formation of inclusion bodies. These inclusion bodies must be denatured and refolded to obtain active protein, and the affinity tails are usefiil in the purification of the protein. Some of the methods described herein involve identification of functional domains in proteins (see also Protein engineering). 

The significance of this novel attempt lies in the inclusion of both the additional particle co-ordinate and in a mechanism of particle disruption by primary particle attrition in the population balance. This formulation permits prediction of secondary particle characteristics, e.g. specific surface area expressed as surface area per unit volume or mass of crystal solid (i.e. m /m or m /kg). It can also account for the formation of bimodal particle size distributions, as are observed in many precipitation processes, for which special forms of size-dependent aggregation kernels have been proposed previously. 

Precisely, this behavior is found for the host 26 (see Sect. 4.1), another properly tailored carboxylic add (cf. Sect. 4.5). The crystal structure of the 1-butanol associate of 26 (Fig. 18 b) shows the same 12-membered H-bond pattern around a center of symmetry as found for the inclusions of I with MeOH, EtOH, and 2-PrOH and exactly the same building principle (dimeric host and 12-ring formation) as in the 1-PrOH aggregate of 1. Thus, they both belong to the same type lib of building blocks (Fig. 19). 

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