RESUMO
Leptin is a signaling protein that in its mutant forms has been associated with obesity and Type II diabetes. The lack of sequence similarity has precluded analogies based on structural resemblance to known systems. Backbone NMR signals for mouse leptin (13C/15N -labeled) have been assigned and its secondary structure reveals it to be a four-helix bundle cytokine. Helix lengths and disulfide pattern are in agreement with leptin as a member of the short-helix cytokine family. A three-dimensional model was built verifying the mechanical consistency of the identified elements with a short-helix cytokine core.
Assuntos
Estrutura Secundária de Proteína , Proteínas/química , Sequência de Aminoácidos , Animais , Isótopos de Carbono , Citocinas/química , Citocinas/classificação , Leptina , Espectroscopia de Ressonância Magnética , Camundongos , Modelos Moleculares , Dados de Sequência Molecular , Isótopos de Nitrogênio , Proteínas/classificaçãoRESUMO
In an effort to prepare 3,4-methylene-dioxyphenyl-(S)-isopropanol from 3,4-methylene-dioxyphenylacetone, an initial screen of microbes indicated that Candida famata could catalyze this reaction efficiently at low substrate concentration. A dilute, large-scale process was developed to provide experimental material for the chemical synthesis to be explored. However, the productivity number of this process [0.134 g product (g wet weight cells)-1 day-1 was too low to be practical. C. famata was also extremely sensitive to concentrations of both the ketone and the alcohol greater than 2 g/l. A more extensive screen of yeast and fungi revealed that Zygosaccharomyces rouxii was more tolerant to higher substrate concentrations and had a higher productivity number [0.8 g (g wet weight cells)-1 day-1]. These characteristics suggested that Z. rouxii could be used in a large-scale process at high substrate concentrations.
