PMID- 10052934
OWN - NLM
STAT- MEDLINE
DCOM- 19990322
LR  - 20071115
IS  - 0006-2960 (Print)
IS  - 0006-2960 (Linking)
VI  - 38
IP  - 9
DP  - 1999 Mar 2
TI  - The structure of human retinol-binding protein (RBP) with its carrier protein
      transthyretin reveals an interaction with the carboxy terminus of RBP.
PG  - 2647-53
AB  - Whether ultimately utilized as retinoic acid, retinal, or retinol, vitamin A is
      transported to the target cells as all-trans-retinol bound to retinol-binding
      protein (RBP). Circulating in the plasma, RBP itself is bound to transthyretin
      (TTR, previously referred to as thyroxine-binding prealbumin). In vitro one
      tetramer of TTR can bind two molecules of retinol-binding protein. However, the
      concentration of RBP in the plasma is limiting, and the complex isolated from
      serum is composed of TTR and RBP in a 1 to 1 stoichiometry. We report here the
      crystallographic structure at 3.2 A of the protein-protein complex of human RBP
      and TTR. RBP binds at a 2-fold axis of symmetry in the TTR tetramer, and
      consequently the recognition site itself has 2-fold symmetry: Four TTR amino
      acids (Arg-21, Val-20, Leu-82, and Ile-84) are contributed by two monomers. Amino
      acids Trp-67, Phe-96, and Leu-63 and -97 from RBP are flanked by the
      symmetry-related side chains from TTR. In addition, the structure reveals an
      interaction of the carboxy terminus of RBP at the protein-protein recognition
      interface. This interaction, which involves Leu-182 and Leu-183 of RBP, is
      consistent with the observation that naturally occurring truncated forms of the
      protein are more readily cleared from plasma than full-length RBP. Complex
      formation prevents extensive loss of RBP through glomerular filtration, and the
      loss of Leu-182 and Leu-183 would result in a decreased affinity of RBP for TTR.
FAU - Naylor, H M
AU  - Naylor HM
AD  - Department of Biochemistry, Vanderbilt University School of Medicine, Nashville, 
      Tennessee 37232-0146, USA.
FAU - Newcomer, M E
AU  - Newcomer ME
LA  - eng
SI  - PDB/1QAB
GR  - GM0820/GM/NIGMS NIH HHS/United States
GR  - GM55420/GM/NIGMS NIH HHS/United States
PT  - Journal Article
PT  - Research Support, U.S. Gov't, P.H.S.
PL  - United States
TA  - Biochemistry
JT  - Biochemistry
JID - 0370623
RN  - 0 (Carrier Proteins)
RN  - 0 (Macromolecular Substances)
RN  - 0 (Peptide Fragments)
RN  - 0 (Prealbumin)
RN  - 0 (Retinol-Binding Proteins)
RN  - 0 (Retinol-Binding Proteins, Plasma)
RN  - 0 (Solutions)
SB  - IM
MH  - Carrier Proteins/chemistry/metabolism
MH  - Crystallization
MH  - Crystallography, X-Ray
MH  - Humans
MH  - Macromolecular Substances
MH  - Models, Molecular
MH  - Peptide Fragments/*chemistry/metabolism
MH  - Prealbumin/*chemistry/metabolism
MH  - Protein Conformation
MH  - Retinol-Binding Proteins/*chemistry/metabolism
MH  - Retinol-Binding Proteins, Plasma
MH  - Solutions
EDAT- 1999/03/03 00:00
MHDA- 1999/03/03 00:01
CRDT- 1999/03/03 00:00
PHST- 1999/03/03 00:00 [pubmed]
PHST- 1999/03/03 00:01 [medline]
PHST- 1999/03/03 00:00 [entrez]
AID - 10.1021/bi982291i [doi]
AID - bi982291i [pii]
PST - ppublish
SO  - Biochemistry. 1999 Mar 2;38(9):2647-53. doi: 10.1021/bi982291i.