Angiotensin-converting enzyme open for business: structural insights into the subdomain dynamics
FEBS JOURNAL
Authors: Cozier, Gyles E.; Lubbe, Lizelle; Sturrock, Edward D.; Acharya, K. Ravi
Abstract
Angiotensin-1-converting enzyme (ACE) is a key enzyme in the renin-angiotensin-aldosterone and kinin systems where it cleaves angiotensin I and bradykinin peptides, respectively. However, ACE also participates in numerous other physiological functions, can hydrolyse many peptide substrates and has various exo- and endopeptidase activities. ACE achieves this complexity by containing two homologous catalytic domains (N- and C-domains), which exhibit different substrate specificities. Here, we present the first open conformation structures of ACE N-domain and a unique closed C-domain structure (2.0 angstrom) where the C terminus of a symmetry-related molecule is observed inserted into the active-site cavity and binding to the zinc ion. The open native N-domain structure (1.85 angstrom) enables comparison with ACE2, a homologue previously observed in open and closed states. An open S-2_S '-mutant N-domain structure (2.80 angstrom) includes mutated residues in the S-2 and S ' subsites that effect ligand binding, but are distal to the binding site. Analysis of these structures provides important insights into how structural features of the ACE domains are able to accommodate the wide variety of substrates and allow different peptidase activities. Database The atomic coordinates and structure factors for Open nACE, Open S2_S '-nACE and Native G13-cACE structures have been deposited with codes , and , respectively, in the RCSB Protein Data Bank,
Clinical Applicability of the Specific Risk Score of Dementia in Type 2 Diabetes in the Identification of Patients with Early Cognitive Impairment: Results of the MOPEAD Study in Spain
JOURNAL OF CLINICAL MEDICINE
Authors: Ortiz Zuniga, Angel Michael; Simo, Rafael; Rodriguez-Gomez, Octavio; Hernandez, Cristina; Rodrigo, Adrian; Jamilis, Laura; Campo, Laura; Alegret, Montserrat; Boada, Merce; Ciudin, Andreea
Abstract
Introduction: Although the Diabetes Specific Dementia Risk Score (DSDRS) was proposed for predicting risk of dementia at 10 years, its usefulness as a screening tool is unknown. For this purpose, the European consortium MOPEAD included the DSDRS within the specific strategy for screening of cognitive impairment in type 2 diabetes (T2D) patients attended in a third-level hospital. Material and Methods: T2D patients > 65 years, without known cognitive impairment, attended in a third-level hospital, were evaluated. As per MOPEAD protocol, patients with MMSE <= 27 or DSDRS >= 7 were referred to the memory clinic for complete neuropsychological assessment. Results: 112 T2D patients were recruited. A total of 82 fulfilled the criteria for referral to the memory unit (43 of them declined referral: 48.8% for associated comorbidities, 37.2% lack of interest, 13.95% lack of social support). At the Fundacio ACE's Memory Clinic, 34 cases (87.2%) of mild cognitive impairment (MCI) and 3 cases (7.7%) of dementia were diagnosed. The predictive value of DSDRS >= 7 as a screening tool of cognitive impairment was AUROC = 0.739,p0.024, CI 95% (0.609-0.825). Conclusions: We found a high prevalence of unknown cognitive impairment in TD2 patients who attended a third-level hospital. The DSDRS was found to be a useful screening tool. The presence of associated comorbidities was the main factor of declining referral.