Structural Investigations into Shwachman Bodian Diamond Syndrome SBDS using a Bioinformatics Approach

The functional correlation of missense mutations which cause disease remains a challenge to understanding the basis of genetic diseases. This is particularly true for proteins related to diseases for which there are no available three dimensional structures. One such disease is Shwachman Diamond syndrome SDS OMIM 260400, a multi system disease arising from loss of functional mutations. The Homo sapiens Shwachman Bodian Diamond Syndrome gene hSBDS is responsible for SDS. hSBDS is expressed in all tissues and encodes a protein of 250 amino acids SwissProt accession code Q9Y3A5. Sequence analysis of disease associated alleles has identified more than 20 different mutations in affected individuals. While a number of these mutations have been described as leading to the loss of protein function due to truncation, translation or surface epitope association, the structural basis for these mutations has yet to be determined due to the lack of a threedimensional structure for SBDS. Moreover, SBDS is a highly conserved gene of unknown function, however, biochemical studies suggest that SBDS may be involved in RNA metabolism or ribosome assembly. Here, we describe a homology model for hSBDS which is based on the crystal structure of AF0491 from Archaeoglobus fulgidus PDB code 1P9Q that shares 24 percent sequence identity and 49 percent similarity with hSBDS. This model provides insights into how the different mutations are involved in translation, truncation, protein protein interactions, protein stability and function.