Monomeric solution structure of the prototypical 'C' chemokine lymphotactin. Biochemistry 2001 Oct 23;40(42):12486-96
Date
10/17/2001Pubmed ID
11601972Pubmed Central ID
PMC3826542DOI
10.1021/bi011106pScopus ID
2-s2.0-0035940521 (requires institutional sign-in at Scopus site) 57 CitationsAbstract
Lymphotactin, the sole identified member of the C class of chemokines, specifically attracts T lymphocytes and natural killer cells. This 93-residue protein lacks 2 of the 4 conserved cysteine residues characteristic of the other 3 classes of chemokines and possesses an extended carboxyl terminus, which is required for chemotactic activity. We have determined the three-dimensional solution structure of recombinant human lymphotactin by NMR spectroscopy. Under the conditions used for the structure determination, lymphotactin was predominantly monomeric; however, pulsed field gradient NMR self-diffusion measurements and analytical ultracentrifugation revealed evidence of dimer formation. Sequence-specific chemical shift assignments were determined through analysis of two- and three-dimensional NMR spectra of (15)N- and (13)C/(15)N-enriched protein samples. Input for the torsion angle dynamics calculations used in determining the structure included 1258 unique NOE-derived distance constraints and 60 dihedral angle constraints obtained from chemical-shift-based searching of a protein conformational database. The ensemble of 20 structures chosen to represent the structure had backbone and heavy atom rms deviations of 0.46 +/- 0.11 and 1.02 +/- 0.14 A, respectively. The results revealed that human lymphotactin adopts the conserved chemokine fold, which is characterized by a three-stranded antiparallel beta-sheet and a C-terminal alpha-helix. Two regions are dynamically disordered as evidenced by (1)H and (13)C chemical shifts and [(15)N]-(1)H NOEs: residues 1-9 of the amino terminus and residues 69-93 of the C-terminal extension. A functional role for the C-terminal extension, which is unique to lymphotactin, remains to be elucidated.
Author List
Kuloglu ES, McCaslin DR, Kitabwalla M, Pauza CD, Markley JL, Volkman BFAuthor
Brian F. Volkman PhD Professor in the Biochemistry department at Medical College of WisconsinMESH terms used to index this publication - Major topics in bold
Amino Acid SequenceAnimals
Chemokines, C
Chickens
Crystallography, X-Ray
Humans
Lymphokines
Macaca mulatta
Mice
Molecular Sequence Data
Nuclear Magnetic Resonance, Biomolecular
Protein Structure, Secondary
Rats
Recombinant Fusion Proteins
Sequence Homology, Amino Acid
Sialoglycoproteins
Solutions
Thermodynamics
