1. CLORE, G.M., APPELLA, E., YAMADA, M., MATSUSHIMA, K. AND GRONENBORN, A.M.
Three-dimensional structure of interleukin 8 in solution.
BIOCHEMISTRY 29 1689-1696 (1990).
2. STUCKEY, J.A., ST. CHARLES, R. AND EDWARDS, B.F.
A model of the platelet factor 4 complex with heparin.
PROTEINS 14 277-287 (1992).
3. BAGGIOLINI, M. AND CLARK-LEWIS, I.
Interleukin-8, a chemotactic and inflammatory cytokine.
FEBS LETT. 307 97-101 (1992).
Certain cell types, such as fibroblasts, endothelial cells and macrophages,
secrete low molecular weight proteins in response to a variety of stimuli,
including viral transformation, interferons and growth factors [1-3]. Some
of these factors are structurally related, existing as either homodimers or
homotetramers: each monomer has a core fold comprising a 3-stranded anti-
parallel beta-sheet in a Greek-key arrangement , and a C-terminal alpha-
helix [1,2]. The structure is held together by 2 disulphide bridges [1,2].
All such cytokine proteins possess mitogenic, chemotactic or inflammatory
activities [1-3], and are referred to as chemokines or intercrines. The
family can be split into 2 groups, depending on the spacing of 2 N-terminal
Cys residues [1,2]: in one group (CxC), the cysteines are separated by a
single amino acid; in the second (CC), they are adjacent [1,2]. The CxC
group includes such factors as interleukin-8, platelet factor 4, melanoma
growth stimulatory activity protein, macrophage inflammatory protein 2,
platelet basic protein, and several others.
SMALLCYTKCXC is a 3-element fingerprint that provides a signature for the
CxC family of chemokines. The fingerprint was derived from an initial
alignment of 16 sequences: the motifs were drawn from conserved regions
spanning virtually the full alignment length - motif 1 encodes the N-
terminal region containing the first 2 cysteines; motif 2 spans the first
2 beta-strands; and motif 3 spans the third strand and part of the C-
terminal helix (the motifs encompass the region encoded by PROSITE pattern
SMALL_CYTOKINES_CXC (PS00471), which describes a large portion of the active
protein). Two iterations on OWL26.3 were required to reach convergence, at
which point a true set comprising 49 sequences was identified.
An update on SPTR37_9f identified a true set of 48 sequences, and 1