PMID- 7538847
OWN - NLM
STAT- MEDLINE
DCOM- 19950626
LR  - 20181113
IS  - 0961-8368 (Print)
IS  - 1469-896X (Electronic)
IS  - 0961-8368 (Linking)
VI  - 3
IP  - 12
DP  - 1994 Dec
TI  - Structure-function analysis of human IL-6: identification of two distinct regions 
      that are important for receptor binding.
PG  - 2280-93
AB  - Interleukin-6 (IL-6) is a multifunctional cytokine that plays an important role 
      in host defense. It has been predicted that IL-6 may fold as a 4 alpha-helix 
      bundle structure with up-up-down-down topology. Despite a high degree of sequence 
      similarity (42%) the human and mouse IL-6 polypeptides display distinct 
      species-specific activities. Although human IL-6 (hIL-6) is active in both human 
      and mouse cell assays, mouse IL-6 (mIL-6) is not active on human cells. 
      Previously, we demonstrated that the 5 C-terminal residues of mIL-6 are important 
      for activity, conformation, and stability (Ward LD et al., 1993, Protein Sci 
      2:1472-1481). To further probe the structure-function relationship of this 
      cytokine, we have constructed several human/mouse IL-6 hybrid molecules. 
      Restriction endonuclease sites were introduced and used to ligate the human and 
      mouse sequences at junction points situated at Leu-62 (Lys-65 in mIL-6) in the 
      putative connecting loop AB between helices A and B, at Arg-113 (Val-117 in 
      mIL-6) at the N-terminal end of helix C, at Lys-150 (Asp-152 in mIL-6) in the 
      connecting loop CD between helices C and D, and at Leu-178 (Thr-180 in mIL-6) in 
      helix D. Hybrid molecules consisting of various combinations of these fragments 
      were constructed, expressed, and purified to homogeneity. The conformational 
      integrity of the IL-6 hybrids was assessed by far-UV CD. Analysis of their 
      biological activity in a human bioassay (using the HepG2 cell line), a mouse 
      bioassay (using the 7TD1 cell line), and receptor binding properties indicates 
      that at least 2 regions of hIL-6, residues 178-184 in helix D and residues 63-113 
      in the region incorporating part of the putative connecting loop AB through to 
      the beginning of helix C, are critical for efficient binding to the human IL-6 
      receptor. For human IL-6, it would appear that interactions between residues 
      Ala-180, Leu-181, and Met-184 and residues in the N-terminal region may be 
      critical for maintaining the structure of the molecule; replacement of these 
      residues with the corresponding 3 residues in mouse IL-6 correlated with a 
      significant loss of alpha-helical content and a 200-fold reduction in activity in 
      the mouse bioassay. A homology model of mIL-6 based on the X-ray structure of 
      human granulocyte colony-stimulating factor is presented.
FAU - Hammacher, A
AU  - Hammacher A
AD  - Joint Protein Structure Laboratory, Ludwig Institute for Cancer Research/Walter 
      and Eliza Hall Institute of Medical Research, Parkville, Victoria, Australia.
FAU - Ward, L D
AU  - Ward LD
FAU - Weinstock, J
AU  - Weinstock J
FAU - Treutlein, H
AU  - Treutlein H
FAU - Yasukawa, K
AU  - Yasukawa K
FAU - Simpson, R J
AU  - Simpson RJ
LA  - eng
PT  - Comparative Study
PT  - Journal Article
PT  - Research Support, Non-U.S. Gov't
PL  - United States
TA  - Protein Sci
JT  - Protein science : a publication of the Protein Society
JID - 9211750
RN  - 0 (Interleukin-6)
RN  - 0 (Receptors, Interleukin)
RN  - 0 (Receptors, Interleukin-6)
RN  - 0 (Recombinant Fusion Proteins)
RN  - 143011-72-7 (Granulocyte Colony-Stimulating Factor)
RN  - 9001-32-5 (Fibrinogen)
SB  - IM
MH  - Amino Acid Sequence
MH  - Animals
MH  - Base Sequence
MH  - Binding, Competitive
MH  - Biosensing Techniques
MH  - Carcinoma, Hepatocellular/pathology
MH  - Circular Dichroism
MH  - Fibrinogen/biosynthesis
MH  - Granulocyte Colony-Stimulating Factor/chemistry
MH  - Humans
MH  - Interleukin-6/*chemistry/metabolism
MH  - Liver Neoplasms/pathology
MH  - Lymphocyte Activation
MH  - Mice
MH  - Models, Molecular
MH  - Multiple Myeloma/pathology
MH  - Protein Binding
MH  - *Protein Conformation
MH  - Receptors, Interleukin/*metabolism
MH  - Receptors, Interleukin-6
MH  - Recombinant Fusion Proteins/*chemistry/metabolism
MH  - Sequence Alignment
MH  - Sequence Homology, Amino Acid
MH  - Species Specificity
MH  - Structure-Activity Relationship
MH  - Tumor Cells, Cultured
PMC - PMC2142761
EDAT- 1994/12/01 00:00
MHDA- 1994/12/01 00:01
PMCR- 1995/06/01
CRDT- 1994/12/01 00:00
PHST- 1994/12/01 00:00 [pubmed]
PHST- 1994/12/01 00:01 [medline]
PHST- 1994/12/01 00:00 [entrez]
PHST- 1995/06/01 00:00 [pmc-release]
AID - 10.1002/pro.5560031213 [doi]
PST - ppublish
SO  - Protein Sci. 1994 Dec;3(12):2280-93. doi: 10.1002/pro.5560031213.