The scavenger receptor cysteine-rich (SRCR) proteins form an archaic group of metazoan proteins characterized by the presence of SRCR domains. These proteins are classified in group A and B based on the number of conserved cysteine residues in their SRCR domains, i.e. six for group A and eight for group B. The protein DMBT1 (deleted in malignant brain tumors 1), which is identical to salivary agglutinin and lung gp-340, belongs to the group B SRCR proteins and is considered to be involved in tumor suppression and host defense by pathogen binding. In a previous study we used nonoverlapping synthetic peptides covering the SRCR consensus sequence to identify a 16-amino acid bacteriabinding protein loop (peptide SRCRP2; QGRVEVLYRG-SWGTVC) within the SRCR domains. In this study, using overlapping peptides, we pinpointed the minimal bacteria-binding site on SRCRP2, and thus DMBT1, to an 11-amino acid motif (DMBT1 pathogen-binding site 1 or DMBT1pbs1; GRVEVLYRGSW). An alanine substitution scan revealed that VEVL and Trp are critical residues in this motif. Bacteria binding by DMBT1pbs1 was different from the bacteria binding by the macrophage receptor MARCO in which an RXR motif was critical. In addition, the homologous consensus sequences of a number of SRCR proteins were synthesized and tested for bacteria binding. Only consensus sequences of DMBT1 orthologues bound bacteria by this motif.The scavenger receptor cysteine-rich (SRCR) 1 proteins form an archaic group of metazoan proteins (1-5). This group of glycoproteins comprises cell surface molecules as well as secreted proteins that are characterized by the presence of one or more SRCR domains. SRCR domains consist of ϳ110 amino acids and are divided into groups A and B based on the number of conserved cysteine residues, namely six for group A and eight for group B.The best studied members of the group A SRCR proteins are the macrophage scavenger receptor (MSR1), the Mac 2-binding protein (Mac-2bp), and MARCO. Both MSR1 and MARCO are known to interact with bacteria (6, 7). In contrast to MARCO (8), the SRCR domain of MSR1 does not seem to be involved in bacteria binding (9, 10). Bacteria binding by MARCO involves an RXR motif within the SRCR domain, indicating that ionic interactions play a crucial role in the interaction with its negatively charged ligands (6).Group B SRCR proteins are generally involved in the regulation of cellular immune responses. In vertebrates, the group B SRCR proteins can be divided, on the basis of their structure and sequence homology, into three subgroups (11). The first subgroup includes CD5 (12), CD6 (13), and SP␣ (14). CD5 and CD6 are composed of an extracellular region of three SRCR domains, a transmembrane region, and a cytoplasmic region. SP␣ lacks the latter two regions but contains three SRCR domains that are highly homologous to those of CD5 and CD6. These three proteins are mainly expressed by T-cells and Bcells (12, 13). The second subgroup of SRCR group B molecules is the workshop cluster 1 (WC1) family, which includes WC1, ...

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Several factors playing a possible role in determining coating stability and bone tissue response were studied in in vivo experiments. These factors involving the plasmaspray coating procedure were as follows: 1) plasmaspray powder port 2 or 6; 2) particle size distribution; 3) hydroxylapatite versus fluorapatite coatings; and 4) the effect of post-heat treatment. Coating stability and bone tissue response were examined by measuring coating thickness, coating length, and bone apposition against the coatings. The result was that heat treatment influenced coating stability significantly. Also, bone formation was more intense. Fluorapatite proved to be more stable than hydroxylapatite, which was in agreement with our previous reports.

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