PDBsum entry 1b6e

Nk cell

PDB id: 1b6e

Contents

Protein chain

121 a.a.

Waters ×39

References listed in PDB file

Key reference

Title

Structure of cd94 reveals a novel c-Type lectin fold: implications for the nk cell-Associated cd94/nkg2 receptors.

Authors

J.C.Boyington, A.N.Riaz, A.Patamawenu, J.E.Coligan, A.G.Brooks, P.D.Sun.

Ref.

Immunity, 1999, 10, 75-82. [DOI no: 10.1016/S1074-7613(00)80008-4]

PubMed id

10023772

Abstract

The crystal structure of the extracellular domain of CD94, a component of the CD94/NKG2 NK cell receptor, has been determined to 2.6 A resolution, revealing a unique variation of the C-type lectin fold. In this variation, the second alpha helix, corresponding to residues 102-112, is replaced by a loop, the putative carbohydrate-binding site is significantly altered, and the Ca2+-binding site appears nonfunctional. This structure may serve as a prototype for other NK cell receptors such as Ly-49, NKR-P1, and CD69. The CD94 dimer observed in the crystal has an extensive hydrophobic interface that stabilizes the loop conformation of residues 102-112. The formation of this dimer reveals a putative ligand-binding region for HLA-E and suggests how NKG2 interacts with CD94.

Figure 2.
Figure 2. Comparison of Human CD94 and Rat MBP-ACD94 is magenta and MBP-A (Brookhaven PDB entry 1RTM) is blue.(A) Loops 3 and 6 in CD94. Side chains displayed are those that play a prominent role in stabilizing loop 3. Acidic residues are red, basic residues are blue, and neutral residues are tan. Two salt bridges are designated by dotted lines.(B) Superposition of the Ca^2+-binding site of rat MBP-A with the same region in the human CD94 structure (loop 5 and β strand 6). Ca^2+-binding residues from MBP-A and potential Ca^2+-binding residues in CD94 are represented by ball-and-stick models.(C) Superimposed and separated ribbon diagrams of the C-type lectin domains from CD94 (left) and MBP-A (right).

Figure 5.
Figure 5. Model of the CD94/NKG2A HeterodimerNKG2A is on the left side of the dimer represented by a light-green ribbon model and CD94 is on the right side represented by a dark-green ribbon model. Each of the charged residues within the putative HLA-E-binding surface is represented by a colored ball at the α carbon position and labeled according to the one-letter amino acid code. Red balls represent acidic residues and dark-blue balls represent basic residues.

The above figures are reprinted by permission from Cell Press: Immunity (1999, 10, 75-82) copyright 1999.