PMID- 7822338
OWN - NLM
STAT- MEDLINE
DCOM- 19950213
LR  - 20210210
IS  - 0021-9258 (Print)
IS  - 0021-9258 (Linking)
VI  - 270
IP  - 2
DP  - 1995 Jan 13
TI  - Structure-function relationships in human interleukin-11. Identification of 
      regions involved in activity by chemical modification and site-directed 
      mutagenesis.
PG  - 978-85
AB  - Chemical modification approaches combined with site-directed and deletion 
      mutagenesis have been used to identify functionally critical regions/residues of 
      recombinant human IL-11 (rhIL-11). Incubation of rhIL-11 with iodoacetic acid 
      results in specific alkylation of a single methionine residue, Met58, and a 
      25-fold reduction of in vitro biological activity on mouse plasmacytoma cells. A 
      similar decrease in activity is observed when Met58 is substituted with Ala, Leu, 
      Gln, Glu, or Lys by site-directed mutagenesis. Treatment of rhIL-11 with succinic 
      anhydride leads to modification of the amino-terminal amino group and partial 
      labeling of 2 lysines, Lys41 and Lys98, and to a 3-fold decrease in activity. The 
      activity losses can be attributed to modification of the lysine residues, since 
      the succinyl derivative of the amino terminus is fully active. In addition, 
      carboxyl-terminal deletion mutagenesis studies have demonstrated that removal of 
      the last 4 residues reduces rhIL-11 activity 25-fold, whereas removal of 8 or 
      more amino acids results in an inactive molecule. Based on secondary structure 
      predictions and the location of exon/intron boundaries in the IL-11 genomic 
      structure, we propose a four-helix bundle topology as a structural model for 
      rhIL-11. This model has been tested by limited proteolysis using three side 
      chain-specific endoproteinases. A limited number of protease-sensitive cleavage 
      sites are present in rhIL-11, and all but two are located in the postulated helix 
      interconnecting loops or at helix termini. alpha-Helices, which in the proposed 
      structure form a compact core of the molecule, are inaccessible to digestion 
      under limiting conditions. According to the model, Met58, Lys41 and Lys98 are 
      located on the surface of the molecule, in agreement with their preferential 
      accessibility to chemical modifications. By analogy with human growth hormone, we 
      postulate that Met58 and the carboxyl terminus of rhIL-11 are involved in the 
      primary receptor binding site (site I), whereas Lys41 and Lys98 may be a part of 
      binding site II.
FAU - Czupryn, M J
AU  - Czupryn MJ
AD  - Genetics Institute, Andover, Massachusetts 01810.
FAU - McCoy, J M
AU  - McCoy JM
FAU - Scoble, H A
AU  - Scoble HA
LA  - eng
PT  - Journal Article
PL  - United States
TA  - J Biol Chem
JT  - The Journal of biological chemistry
JID - 2985121R
RN  - 0 (Interleukin-11)
RN  - 0 (Recombinant Proteins)
RN  - AE28F7PNPL (Methionine)
RN  - K3Z4F929H6 (Lysine)
SB  - IM
MH  - Amino Acid Sequence
MH  - Humans
MH  - Interleukin-11/chemistry/genetics/*physiology
MH  - Lysine/chemistry
MH  - Methionine/chemistry
MH  - Models, Molecular
MH  - Molecular Sequence Data
MH  - Mutagenesis, Site-Directed
MH  - Recombinant Proteins/chemistry/genetics
MH  - Structure-Activity Relationship
EDAT- 1995/01/13 00:00
MHDA- 1995/01/13 00:01
CRDT- 1995/01/13 00:00
PHST- 1995/01/13 00:00 [pubmed]
PHST- 1995/01/13 00:01 [medline]
PHST- 1995/01/13 00:00 [entrez]
AID - S0021-9258(18)83100-3 [pii]
AID - 10.1074/jbc.270.2.978 [doi]
PST - ppublish
SO  - J Biol Chem. 1995 Jan 13;270(2):978-85. doi: 10.1074/jbc.270.2.978.