Crystal structure of peptide-bound neprilysin reveals key binding interactions

Neprilysin (NEP) is a promiscuous zinc metalloprotease with broad substrate specificity and cleaves a remarkable diversity of substrates through endopeptidase action. Two of these – amyloid-β and natriuretic peptides – implicate the enzyme in both Alzheimer’s disease and cardiovascular disease, respectively. Here, we report the creation of a catalytically inactive NEP (E584D) to determine the first peptide-bound crystal structure at 2.6 Å resolution. The structure reveals key interactions involved in substrate binding which we have identified to be conserved in other known zinc metalloproteases. In addition, the structure provides evidence for a potential exosite within the central cavity that may play a critical role in substrate positioning. Together, these results contribute to our understanding of the molecular function of NEP.</p

Structure of mouse IP-10, a chemokine

The structure of mouse IP-10 shows a novel tetrameric association

C9orf72, a protein associated with amyotrophic lateral sclerosis (ALS) is a guanine nucleotide exchange factor

Amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD), two late onset neurodegenerative diseases, have been shown to share overlapping cellular pathologies and genetic origins. Studies suggest that a hexanucleotide repeat expansion in the first intron of the C9orf72 gene is the most common cause of familial FTD and ALS pathology. The C9orf72 protein is predicted to be a differentially expressed in normal and neoplastic cells domain protein implying that C9orf72 functions as a guanine nucleotide exchange factor (GEF) to regulate specific Rab GTPases. Reported studies thus far point to a putative role for C9orf72 in lysosome biogenesis, vesicular trafficking, autophagy and mechanistic target of rapamycin complex1 (mTORC1) signaling. Here we report the expression, purification and biochemical characterization of C9orf72 protein. We conclusively show that C9orf72 is a GEF. The distinctive presence of both Rab- and Rho-GTPase GEF activities suggests that C9orf72 may function as a dual exchange factor coupling physiological functions such as cytoskeleton modulation and autophagy with endocytosis

The Design and Development of a Potent and Selective Novel Diprolyl Derivative That Binds to the N-Domain of Angiotensin-I Converting Enzyme

Angiotensin-I converting enzyme (ACE) is a zinc metallo­protease consisting of two catalytic domains (N- and C-). Most clinical ACE inhibitor(s) (ACEi) have been shown to inhibit both domains nonselectively, resulting in adverse effects such as cough and angioedema. Selectively inhibiting the individual domains is likely to reduce these effects and potentially treat fibrosis in addition to hypertension. ACEi from the GVK Biosciences database were inspected for possible N-domain selective binding patterns. From this set, a diprolyl chemical series was modeled using docking simulations. The series was expanded based on key target interactions involving residues known to impart N-domain selectivity. In total, seven diprolyl compounds were synthesized and tested for N-domain selective ACE inhibition. One compound with an aspartic acid in the P₂ position (compound <b>16</b>) displayed potent inhibition (<i>K</i>_i = 11.45 nM) and was 84-fold more selective toward the N-domain. A high-resolution crystal structure of compound <b>16</b> in complex with the N-domain revealed the molecular basis for the observed selectivity

Identification of Placenta Growth Factor Determinants for Binding and Activation of Flt-1 Receptor

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