Trehalose transporter

Xavier, K. B., L. O. Martins, R. Peist, M. Kossmann, W. Boos, and H. Santos. 1996. High-affinity maltose/trehalose transport system in the hyperthermophilic archaeon Thermococcus litoralis. Journal of Bacteriology 178 4773—4777. 

S. typhimurium normally transport trehalose via the galactose permease and are able to grow on this substrate in the complete absence of PTS phosphorylating activity. However, in S. typhimurium which lack a functional galactose permease, IfMan appears to be able to transport trehalose [78]. There is no evidence that trehalose is phosphorylated in this process, again pointing to Il "-dependent transport in the facilitated diffusion mode. 

Diederichs, K, Diez, J., Greller, G., Muller, C., Breed, J., Schnell, C., Vonrhein, C., Boos, W. and Welte, W. (2000). Crystal structure of MalK, the ATPase subunit of the trehalose/maltose ABC transporter of the archaeon Thermococcus litoralis, EMBO J., 19, 5951-5961. 

Complexes of alkali metals and alkaline-earth metals with carbohydrates have been reviewed in this Series,134 and the interaction of alkaline-earth metals with maltose has been described.135 Standard procedures for the preparation of adducts of D-glucose and maltose with the hydroxides of barium, calcium, and strontium have been established. The medium most suitable for the preparation of the adduct was found to be 80% methanol. It is of interest that the composition of the adducts, from D-glucose, maltose, sucrose, and a,a-trehalose was the same, namely, 1 1, in all cases. The value of such complex-forming reactions in the recovery of metals from industrial wastes has been recognized. Metal hydroxide-sugar complexes may also play an important biological role in the transport of metal hydroxides across cell membranes. 

Trehalose, or "mushroom sugar," is found not only in fungi but also in many other organisms.39 41. It serves as the primary transport sugar in the hemolymph of insects and also acts as an "antifreeze" in many species. 

The above complex means by which fats are mobilized contrast strikingly with the way carbohydrates are mobilized in large part due to the different chemical properties of glucose versus FFAs. As in the case of FFAs, carbohydrates often need to be mobilized from a central depot (in this case, the liver) to sites of utilization at working tissues and the transported metabolite in animals is almost always glucose (there are some invertebrates which use trehalose or galactose). Glucose is a very water... 

Mycolic acids are synthesized inside the cell, and then transferred to trehalose-6-phosphate to yield trehalose monomycolate (TMM), which is thought to be moved outside the cell through an ABC transporter. The mycolic acids are then attached to the arabinogalactan complex by a mycolyltransferase. The intracellular synthesis of the mycolic acids in M. tuberculosis is fairly well understood, and the mycolyltransferase responsible for peptidoglycan attachment has been identified. The intermediate processing steps, however, remain speculative. Synthesis of the mycolic acids has been recently reviewed by Takayama et al. [273], and will not be discussed in detail here. 

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