Cyclopropanated fatty acids

Tipton CL, NM Al-Shathir (1974) The metabolism of cyclopropane fatty acids by Tetrahymena pyriformis. J Biol Chem 249 886-889. 

Among these were a cyclopropane fatty acid from Sterculia foetida (Sterculiaceae) seed oil (0.1%) and cyanolipids from Koelreuteri a... 

Fatty acids containing one or more cyclopropane rings are present in many bacteria (p. 381).124 125 The extra carbon of the cyclopropane ring is added from S-adenosylmethionine (AdoMet) at the site of a cis double bond in a fatty acyl group of a phosphatidyle-thanolamine molecule in a membrane (Eq. 21-4).126/1263 The same type of intermediate carbocation can yield either a cyclopropane fatty acid (Eq. 21-4, step a) or a methenyl fatty acid (Eq. 21-4, step b). The latter can be reduced to a branched fatty acid. This is an alternative way of introducing methyl branches that is used by some bacteria.127... 

But chrysanthemic acid derivatives are by far not the only examples of cyclopropane-containing structures in nature. In fact, the highly strained three-membered carbocycle is virtually ubiquitous. It occurs, for example, in every green plant in the form of 1-aminocyclopropanecarboxylic acid (ACC) 2, a direct precursor to the plant hormone ethylene [3]. In addition, the cyclopropane unit is found in a variety of other natural products, inter alia in terpenes and in various cyclopropanated fatty acids [4]. The biochemical precursors of the latter are unsaturated fatty acids, and in view of the existence of polyunsaturated fatty... 

Will the melting point of lactobacillic acid (Ci9H36C>2, a cyclopropane fatty acid) be higher or lower than that of the linear, saturated fatty acid of the same chain length ... 

Bao XM, Katz S, Pollard M, Ohlrogge J. Carbocyclic fatty acids in plants biochemical and molecular genetic characterization of cyclopropane fatty acid synthesis of Sterculia foetida. Proc. Natl. Acad. Sci. U.S.A. 2002 99 7171-7177. 

Cyclic fatty acids with a carbon ring alone or at the end of the alkyl chain occur naturally in plants, especially in certain seed oils and in microorganisms. Cyclopropane fatty acids are reported occasionally from marine animals and may be synthesized by symbiotic bacteria. In addition, a variety of carbocyclic structures are formed from methylene-intermpted polyenes during food processing. 

The cyclopropane fatty acid, cw-11,12-methylene-octadeca-noic acid, was reported first for Lactobacillus arabinosus and was given the trivial name lactobacillic acid. By now, fatty acids with a mid-chain cyclopropane group have been found in many bacterial species, including aerobic, anaerobic. Gram-negative,... 

Iwig DF, Grippe AT, McIntyre TA, Booker SJ. Isotope and elemental effects indicate a rate-limiting methyl transfer as the initial step in the reaction catalyzed by Escherichia coli cyclopropane fatty acid synthase. Biochemistry 2004 43 13510-13524. 

Courtois E, Ploux O. Escherichia coli cyclopropane fatty acid synthase is a bound bicarbonate ion the active-site base Biochemistry 2005 44 13583-13590. 

The accumulation of cyclopropane fatty acid-containing phospholipids is promoted in bacteria by low pH and low p02, conditions which attend entrance into stationary phase cultures. The conversion of olefin to cyclopropane alters membrane fluidity and probably other functional parameters as well and may be a physiological response to altered environmental conditions. 

Increased acid tolerance correlates strongly with a decrease in proton accumulation in the cytoplasm. This altered proton permeability is again associated with changes in the protein composition of the cell membranes. Acid-adapted E. coli changes the lipid composition of its membranes, and elevated levels of cyclopropane fatty acids are often found. This may mean that changes in the protein composition of the cell membrane are a result of changes in the membrane lipid composition. Both lipid and protein alterations may be necessary to protect a bacterial cell in acidic environments (Jordan, Oxford, and O Byrne, 1999). 

Brown, J.L., Ross, T., McMeekin, T.A., and Nichols, P.D. 1997. Acid habituation of Escherichia coli and the potential role of cyclopropane fatty acids in low pH tolerance. International Journal of Food Microbiology 37 163-173. 

Guerard, C., Breard, M., Courtois, F., Drujon, T., and Ploux, O. (2004) Synthesis and evaluation of analogues of S-adenosyl-L-methionine, as inhibitors of the E. coli cyclopropane fatty acid synthase. Bioorcf. Med. Chem. Lett. 14, 1661-1664. 

A genus of bacteria, termed the Sphingobacterium, produces sphingolipids by a pathway similar to that in mammals. Clostridia produce plasmalogens (l-alk-l -enyl lipids) by an anaerobic pathway clearly different from the Oj-dependent pathway in mammals (Chapter 9). Branched-chain fatty acids are also found in which the methyl group is inserted post-synthetically into the middle of the chain, in a manner analogous to cyclopropane fatty acid synthesis (Section 5.5). S-adenosylmethionine is also the methyl donor for these reactions. The biochemistry surrounding the formation of these and many other bacterial phospholipids remains to be elucidated. 

A similar mycolic acid formed by M. smegmatis has double bonds instead of cyclopropane rings as indicated below Eq. 21-5. 429 jhere are other variations. In place of a double bond or cyclopropane group there may be -OH, -OCH3, C=0, epoxide, or CH3 Cyclopropane fatty acids are catabolized via p oxidation, which is modified as in Eq. 21-6 when the chain degradation reaches the cyclopropane ring. The... 

Bao X, Thelen JJ, Bonaventure G, Ohlrogge JB. (2003) Characterization of cyclopropane fatty-acid synthase from Sterculia foetida. J Biol Chem 278 12846-12853. 

Grogan DW, Cronan JE Jr. (1984) Cloning and manipulation of the Escherichia coli cyclopropane fatty acid synthase gene physiological aspects of enzyme overproduction. JBacterial 158 286-295. 

Pohl, S., H. J. Law, and R. Ryhage Path of hydrogen in the formation of cyclopropane fatty acids. Biochim. Biophysica Acta (Amsterdam) 70, 583 (1963). 

Last, it should be pointed out that no information exists on the influence of fatty acid structure on its micellar solubility in bile acid solutions. It would be of interest to compare branched-chain fatty acids, cyclopropane fatty acids, hydroxy fatty acids, etc. 

EN] PLANT CYCLOPROPANE FATTY ACID SYNTHASE GENES AND USES THEREOF [FR]... 

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