Related Experiment Video
Updated: Aug 8, 2026

A Guide to Production, Crystallization, and Structure Determination of Human IKK1/α
Published on: November 2, 2018
Crystal structure of interleukin-10 reveals the functional dimer with an unexpected topological similarity to
A Zdanov1, C Schalk-Hihi, A Gustchina
1Macromolecular Structure Laboratory, NCI-Frederick Cancer Research and Development Center, Maryland 21702, USA.
Background:
Interleukin (IL)-10 is a cytokine that inhibits production of other regulatory factors, including interferon gamma (IFN-gamma) and IL-2. A dimer of IL-10 is present in solution and is presumed to participate in receptor binding, but the nature of the dimer has not been previously reported. An atomic model is necessary to interpret biological activity of IL-10 and to design mutants with agonistic or antagonistic properties.
Results:
The X-ray crystal structure of a recombinant form of human IL-10 has been solved at 1.8 A resolution and refined to a crystallographic R-factor of 0.156. The molecule is a tight dimer made of two interpenetrating subunits, forming a V-shaped structure. Each half of the structure consists of a six alpha-helices, four originating from one subunit and two from the other. Four of the helices form a classical 'up-up-down-down' bundle observed in all other helical cytokines. The overall topology of the helices bears close resemblance to IFN gamma, although the similarity is less striking when examined in greater detail.
Conclusions:
The topological similarity of IL-10 to IFN gamma was totally unexpected, and may be a reflection of the close relationship between the biological effects of these two cytokines. The structure of IL-10 provides insights into the possible modes of conversion of the dimer into monomers, and of putative sites of receptor interactions. The good level of refinement and high resolution of this structure show that the internal disorder often associated with other helical cytokines is not an essential feature of this class of proteins.
Related Concept Videos
Gene Families
Occasionally these regions can be adapted to take on new roles within the organism, becoming novel genes...
Globular and Fibrous Proteins
Globular proteins are also known as spheroproteins and typically are approximately round in shape. They contain a mix of amino acid types and contain differing sequences in their primary structures. Globular proteins have many different functions, such as enzymes, cellular messengers, and molecular transporters. These roles often require the proteins to be...
Intrinsically Disordered Proteins
Protein-protein Interfaces
The JAK-STAT Signaling Pathway
T Cell Types and Functions
Th1 cells stimulate dendritic cells to express necessary co-stimulatory molecules on their surfaces for...

