Corynebacterium glutamicum genes encoding proteins involved in homeostasis and adaptation

Abstract

Isolated nucleic acid molecules, designated HA nucleic acid molecules, which encode novel HA proteins from Corynebacterium glutamicum are described. The invention also provides antisense nucleic acid molecules, recombinant expression vectors containing HA nucleic acid molecules, and host cells into which the expression vectors have been introduced. The invention still further provides isolated HA proteins, mutated HA proteins, fusion proteins, antigenic peptides and methods for the improvement of production of a desired compound from C. glutamicum based on genetic engineering of HA genes in this organism.

Description

RELATED APPLICATIONS [0001] This application is a continuation application of U.S. patent application Ser. No. 09 / 602,777, filed on Jun. 23, 2000 (allowed), which claims priority to prior filed U.S. Provisional Patent Application Ser. No. 60 / 141,031, filed Jun. 25, 1999. This application also claims priority to prior filed German Patent Application No. 19931636.8, filed Jul. 8, 1999, German Patent Application No. 19932125.6, filed Jul. 9, 1999, German Patent Application No. 19932126.4, filed Jul. 9, 1999, German Patent Application No. 19932127.2, filed Jul. 9, 1999, German Patent Application No. 19932128.0, filed Jul. 9, 1999, German Patent Application No. 19932129.9, filed Jul. 9, 1999, German Patent Application No. 19932226.0, filed Jul. 9, 1999, German Patent Application No. 19932920.6, filed Jul. 14, 1999, German Patent Application No. 19932922.2, filed Jul. 14, 1999, German Patent Application No. 19932924.9, filed Jul. 14, 1999, German Patent Application No. 19932928.1, filed J...

AI Technical Summary

Benefits of technology

[0005]C. glutamicum is a gram positive, aerobic bacterium which is commonly used in industry for the large-scale production of a variety of fine chemicals, and also for the degradation of hydrocarbons (such as in petroleum spills) and for the oxidation of terpenoids. The HA nucleic acid molecules of the invention, therefore, can be used to identify microorganisms which can be used to produce fine chemicals, e.g., by fermentation processes. Modulation of the expression of the HA nucleic acids of the invention, or modification of the sequence of the HA nucleic acid molecules of the invention, can be used to modulate the production of one or more fine chemicals from a microorganism (e.g., to improve the yield or production of one or more fine chemicals from a Corynebacterium or Brevibacterium species).

[0009] There are a number of mechanisms by which the alteration of an HA protein of the invention may directly affect the yield, production, and / or efficiency of production of a fine chemical from a C. glutamicum strain incorporating such an altered protein. For example, by engineering enzymes which modify or degrade aromatic or aliphatic compounds such that these enzymes are increased or decreased in activity or number, it may be possible to modulate the production of one or more fine chemicals which are the modification or degradation products of these compounds. Similarly, enzymes involved in the metabolism of inorganic compounds provide key molecules (e.g. phosphorous, sulfur, and nitrogen molecules) for the biosynthesis of such fine chemicals as amino acids, vitamins, and nucleic acids. By altering the activity or number of these enzymes in C. glutamicum, it may be possible to increase the conversion of these inorganic compounds (or to use alternate inorganic compounds) to thus permit improved rates of incorporation of inorganic atoms into these fine chemicals. Genetic engineering of C. glutamicum enzymes involved in general cellular processes may also directly improve fine chemical production, since many of these enzymes directly modify fine chemicals (e.g., amino acids) or the enzymes which are involved in fine chemical synthesis or secretion. Modulation of the activity or number of cellular proteases may also have a direct effect on fine chemical production, since many proteases may degrade fine chemicals or enzymes involved in fine chemical production or breakdown.

[0010] Further, the aforementioned enzymes which participate in aromatic / aliphatic compound modification or degradation, general biocatalysis, inorganic compound metabolism or proteolysis are each themselves fine chemicals, desirable for their activity in various in vitro industrial applications. By altering the number of copies of the gene for one or more of these enzymes in C. glutamicum it may be possible to increase the number of these proteins produced by the cell, thereby increasing the potential yield or efficiency of production of these proteins from large-scale C. glutamicum or related bacterial cultures.

[0011] The alteration of an HA protein of the invention may also indirectly affect the yield, production, and / or efficiency of production of a fine chemical from a C. glutamicum strain incorporating such an altered protein. For example, by modulating the activity and / or number of those proteins involved in the construction or rearrangement of the cell wall, it may be possible to modify the structure of the cell wall itself such that the cell is able to better withstand the mechanical and other stresses present during large-scale fermentative culture. Also, large-scale growth of C. glutamicum requires significant cell wall production. Modulation of the activity or number of cell wall biosynthetic or degradative enzymes may allow more rapid rates of cell wall biosynthesis, which in turn may permit increased growth rates of this microorganism in culture and thereby increase the number of cells producing the desired fine chemical.

[0012] By modifying the HA enzymes of the invention, one may also indirectly impact the yield, production, or efficiency of production of one or more fine chemicals from C. glutamicum. For example, many of the general enzymes in C. glutamicum may have a significant impact on global cellular processes (e.g., regulatory processes) which in turn have a significant effect on fine chemical metabolism. Similarly, proteases, enzymes which modify or degrade possibly toxic aromatic or aliphatic compounds, and enzymes which promote the metabolism of inorganic compounds all serve to increase the viability of C. glutamicum. The proteases aid in the selective removal of misfolded or misregulated proteins, such as those that might occur under the relatively stressful environmental conditions encountered during large-scale fermentor culture. By altering these proteins, it may be possible to further enhance this activity and to improve the viability of C. glutamicum in culture. The aromatic / aliphatic modification or degradation proteins not only serve to detoxify these waste compounds (which may be encountered as impurities in culture medium or as waste products from cells themselves), but also to permit the cells to utilize alternate carbon sources if the optimal carbon source is limiting in the culture. By increasing their number and / or activity, the survival of C. glutamicum cells in culture may be enhanced. The inorganic metabolism proteins of the invention supply the cell with inorganic molecules required for all protein and nucleotide (among others) synthesis, and thus are critical for the overall viability of the cell. An increase in the number of viable cells producing one or more desired fine chemicals in large-scale culture should result in a concomitant increase in the yield, production, and / or efficiency of production of the fine chemical in the culture.

Problems solved by technology

However, selection of strains improved for the production of a particular molecule is a time-consuming and difficult process.