title: Crystallization of Enantiomerically Pure Proteins from Quasi-Racemic Mixtures: Structure Determination by X-Ray Diffraction of Isotope-Labeled Ester Insulin and Human Insulin.
abstract: As a part of a program aimed towards the study of the dynamics of human insulin-protein dimer formation using two-dimensional infrared spectroscopy, we used total chemical synthesis to prepare stable isotope labeled [(1-(13) C=(18) O)Phe(B24) )] human insulin, via [(1-(13) C=(18) O)Phe(B24) )] ester insulin as a key intermediate product that facilitates folding of the synthetic protein molecule (see preceding article). Here, we describe the crystal structure of the synthetic isotope-labeled ester insulin intermediate and the product synthetic human insulin. Additionally, we present our observations on hexamer formation with these two proteins in the absence of phenol derivatives and/or Zn metal ions. We also describe and discuss the fractional crystallization of quasi-racemic protein mixtures containing each of these two synthetic proteins.
authors.affiliation: Department of Chemistry, University of Chicago, 929 East 57th Street, Chicago, IL, 60637, USA. kmandalt@uchicago.edu.
authors.forename: Kalyaneswar
authors.initials: K
authors.lastname: Mandal
authors.affiliation: Department of Chemistry, University of Chicago, 929 East 57th Street, Chicago, IL, 60637, USA.
authors.forename: Balamurugan
authors.initials: B
authors.lastname: Dhayalan
authors.affiliation: Department of Chemistry, University of Chicago, 929 East 57th Street, Chicago, IL, 60637, USA.
authors.forename: Michal
authors.initials: M
authors.lastname: Avital-Shmilovici
authors.affiliation: Department of Chemistry, University of Chicago, 929 East 57th Street, Chicago, IL, 60637, USA.
authors.forename: Andrei
authors.initials: A
authors.lastname: Tokmakoff
authors.affiliation: Department of Chemistry, University of Chicago, 929 East 57th Street, Chicago, IL, 60637, USA.
authors.forename: Stephen B H
authors.initials: SB
authors.lastname: Kent
mesh_terms: D003460:Crystallization; D018360:Crystallography, X-Ray; D004952:Esters; D007328:Insulin / Q000737:chemistry*; D007553:Isotope Labeling; D008958:Models, Molecular; D011487:Protein Conformation; D011506:Proteins / Q000737:chemistry*; D013237:Stereoisomerism
chemical_list: D004952:Esters; D007328:Insulin; D011506:Proteins
keywords: chemically synthesized proteins; fractional crystallization; human insulin; protein structures; x-ray diffraction