Dynamic Interchanging Native States of Lymphotactin Examined by SNAPP-MS

The human chemokine lymphotactin (Ltn) is a remarkable protein that interconverts between two unrelated native state structures in the condensed phase. It is possible to shift the equilibrium toward either conformation with selected sequence substitutions. Previous results have shown that a disulfide-stabilized variant preferentially adopts the canonical chemokine fold (Ltn10), while a single amino acid change (W55D) favors the novel Ltn40 dimeric structure. Selective noncovalent adduct protein probing (SNAPP) is a recently developed method for examining solution phase protein structure. Herein, it is demonstrated that SNAPP can easily recognize and distinguish between the Ltn10 and Ltn40 states of lymphotactin in aqueous solution. The effects of organic denaturants, acid, and disulfide bond reduction and blocking were also examined using SNAPP for the CC3, W55D, and wild type proteins. Only disulfide reduction was shown to significantly perturb the protein, and resulted in considerably decreased adduct formation consistent with loss of tertiary/secondary structure. Cold denaturation experiments demonstrated that wild-type Ltn is the most temperature sensitive of the three proteins. Examination of the higher charge states in all experiments, which are presumed to represent transition state structures between Ltn-10 and Ltn-40, reveals increased 18C6 attachment relative to the more folded structures. This observation is consistent with increased competitive intramolecular hydrogen bonding, which may guide the transition. Experiments examining the gas phase structures revealed that all three proteins can be structurally distinguished in the gas phase. In addition, the gas phase experiments enabled identification of preferred adduct binding sites

Decreased serum levels of brain-derived neurotrophic factor in schizophrenic patients with deficit syndrome

Esra Soydas Akyol,1 Yakup Albayrak,2 Murat Beyazyüz,3 Nurkan Aksoy,4 Murat Kuloglu,5 Kenji Hashimoto6 1Deparment of Psychiatry, Yenimahalle Education and Research Hospital, Ankara, Turkey; 2Department of Psychiatry, Faculty of Medicine, Namik Kemal University, Tekirdag, Turkey; 3Department of Psychiatry, Biga State Hospital, Çanakkale, Turkey; 4Department of Biochemistry, Yenimahalle Education and Research Hospital, Ankara, Turkey; 5Department of Psychiatry, Faculty of Medicine, Akdeniz University, Antalya, Turkey; 6Division of Clinical Neuroscience, Chiba University Center for Forensic Mental Health, Chiba, Japan Background: Brain-derived neurotrophic factor (BDNF) is a well-established neurotrophin that plays a role in the pathophysiology of numerous psychiatric disorders. Many studies have investigated the serum BDNF levels in patients with schizophrenia. However, there are restricted data in the literature that compare the serum BDNF levels in patients with deficit and nondeficit syndromes. In this study, we aimed to compare the serum BDNF levels between schizophrenic patients with deficit or nondeficit syndrome and healthy controls.Methods: After fulfilling the inclusion and exclusion criteria, 58 patients with schizophrenia and 36 healthy controls were included in the study. The patients were grouped as deficit syndrome (N=23) and nondeficit syndrome (N=35) according to the Schedule for the Deficit Syndrome. Three groups were compared in terms of the sociodemographic and clinical variants and serum BDNF levels.Results: The groups were similar in terms of age, sex, body mass index, and smoking status. The serum BDNF levels in patients with deficit syndrome were significantly lower than those in healthy controls. In contrast, the serum BDNF levels in patients with nondeficit syndrome were similar to those in healthy controls.Conclusion: This study suggests that decreased BDNF levels may play a role in the pathophysio­logy of schizophrenic patients with deficit syndrome. Nonetheless, additional studies using a larger patient sample size are needed to investigate the serum BDNF levels in schizophrenic patients with deficit syndrome. Keywords: biomarker, neurotrophin, psychosi

Increased serum levels of apoptosis in deficit syndrome schizophrenia patients: a preliminary study

Murat Beyazyüz,1 Tarkan Küfeciler,2 Leyla Bulut,3 Cüneyt Ünsal,1 Yakup Albayrak,1 Esra Soydaş Akyol,4 Saliha Baykal,1 Murat Kuloglu,5 Kenji Hashimoto61Department of Psychiatry, Faculty of Medicine, Namik Kemal University, Tekirdag, Turkey; 2Department of Emergency Medicine, Çekirge State Hospital, Bursa, Turkey; 3Department of Biochemistry, Okmeydani Education and Research Hospital, Istanbul, Turkey; 4Department of Psychiatry, Yenimahalle Education and Research Hospital, Ankara, Turkey; 5Department of Psychiatry, Faculty of Medicine, Akdeniz University, Antalya, Turkey; 6Division of Clinical Neuroscience, Chiba University Center for Forensic Mental Health, Chiba, JapanBackground: Schizophrenia is a chronic and debilitating disorder, the etiology of which remains unclear. Apoptosis is a programmed cell death mechanism that might be implicated in neuropsychiatric disorders, including schizophrenia. In this study, we aimed to compare the serum levels of apoptosis among deficit schizophrenia (DS) syndrome patients, nondeficit schizophrenia (NDS) patients, and healthy controls (HCs).Patients and methods: After the inclusion and exclusion criteria were applied, 23 DS patients, 46 NDS patients, and 33 HCs were included in the study. The serum apoptosis levels were measured using a quantitative sandwich enzyme immunoassay with human monoclonal antibodies directed against DNA and histones.Results: There was a significant difference among the three groups in terms of the levels of apoptosis (F2,96=16.58; P<0.001). The serum apoptosis levels in the DS and NDS groups were significantly higher than those in the HC group. Furthermore, the serum apoptosis levels in the DS group were significantly higher than the levels in the NDS group.Conclusion: This study suggests that increased levels of apoptosis may be implicated in the pathophysiology of DS syndrome. However, further studies are needed to support the role of apoptosis in DS.Keywords: apoptosis, etiology, deficit, psychosi