Covalent structure of two novel neutrophile leucocyte‐derived proteins of porcine and human origin

Abstract

The covalent structures of two, novel, neutrophile, leucocyte-derived, strongly basic proteins of porcine and human origin have been determined by microsequencing in combination with time-of-flight plasma desorption mass spectrometry. The porcine protein primary structure of 219 amino acid residues was shown to contain 6 cysteine residues, 2 putative carbohydrate sites and 14% basic residues. The human protein contained 221 amino acid residues of which 8 were cysteine, 4 putative carbohydrate sites and 12% basic. A 47% direct sequence similarity to human neutrophile elastase was found, but due to mutations of two of the three amino acids in the catalytic triad, proteolytic activity is absent. Modelling and alignment studies unveil a close relationship of both proteins to the serine protease family, the greatest similarity being to those serine proteases present in granules from peripheral blood cells. Both proteins have been shown to be chemotactically active for monocytes and fibroblasts in vitro.

Characterization of recombinant human HBP/CAP37/azurocidin, a pleiotropic mediator of inflammation‐enhancing LPS‐induced cytokine release from monocytes

“…Based on the human HBP amino acid sequence [3] and the CAP37/ azurocidin cDNA sequence [8,9] a 770 bp BamHI HindlII fragment was constructed by PCR technology by usage of a human bone marrow cDNA library (Clontech). This fragment contains the entire coding region of HBP, including a 19-residue signal peptide, a 7 amino acid pro-peptide, a mature part of 222 amino acids, and a 3 amino acid C-terminal extension.…”

“…Heparin-binding protein (HBP), also termed CAP37 [1] and azurocidin [2], is a human neutrophil-derived serine protease homologue exhibiting 45% sequence identity to neutrophil elastase, and 30-37% identity to several other granule serine proteases [3,4]. Despite these similarities, HBP is devoid of proteolytic activity because the active site residues serine and histidine have been replaced.…”

“…Despite these similarities, HBP is devoid of proteolytic activity because the active site residues serine and histidine have been replaced. Beside its lipopolysaccharide (LPS) binding capacity and antimicrobial action [2,5], HBP has been shown to be a specific and strong chemoattractant for monocytes in vitro and to induce longevity and differentiation of these cells towards a macrophage phenotype [1,3]. In addition, HBP has been shown to induce detachment and homotypic aggregation on confluent monolayers of endothelial cells and fibroblasts [6].…”

Neutrophil-derived azurocidin alarms the immune system

“…Somewhat later, Gabay et al [15] characterized a PMN-derived bactericidal protein from the azurophilic granules of human PMN, which they named azurocidin. In parallel, Flodgaard et al [16] isolated a protein from human and porcine PMN that displayed strong binding capability for heparin, earning it the name HBP. Complete sequencing has shown that CAP37, azurocidin, and HBP are the same protein.…”

Binding of bovine pancreatic trypsin inhibitor to heparin binding protein/CAP37/azurocidin

“…In a newly discovered protein, which is highly similar to hepatocyte growth factor and which possesses putative tumor suppressor properties (Han et al, 1991) all three residues of the triad, including Aspl02, have been mutated. We have recently identified yet another example of such a non-enzymatic, active-site-mutated member of the serine proteinase family (Flodgaard et al, 1991). The protein was characterized by a high affinity for heparin and termed 'heparin binding protein' (HBP).…”