Substrate binding and sequence preference of the proteasome revealed by active-site-directed affinity probes.
نویسندگان
چکیده
BACKGROUND The proteasome is a multicatalytic protease complex responsible for most cytosolic protein breakdown. The complex has several distinct proteolytic activities that are defined by the preference of each for the carboxyterminal (P1) amino acid residue. Although mutational studies in yeast have begun to define substrate specificities of individual catalytically active beta subunits, little is known about the principles that govern substrate hydrolysis by the proteasome. RESULTS A series of tripeptide and tetrapeptide vinyl sulfones were used to study substrate binding and specificity of the proteasome. Removal of the aromatic amino-terminal cap of the potent tripeptide vinyl sulfone proteasome inhibitor 4-hydroxy-3-iodo-2-nitrophenyl-leucinyl-leucinyl-leucine vinyl sulfone resulted in the complete loss of binding and inhibition. Addition of a fourth amino acid (P4) to the tri-leucine core sequence fully restored inhibitory potency. 125I-labeled peptide vinyl sulfones were also used to examine inhibitor binding and to determine the correlation of subunit modification with inhibition of peptidase activity. Changing the amino acid in the P4 position resulted in dramatically different profiles of beta-subunit modification. CONCLUSIONS The P4 position, distal to the site of hydrolysis, is important in defining substrate processing by the proteasome. We observed direct correlations between subunit modification and inhibition of distinct proteolytic activities, allowing the assignment of activities to individual beta subunits. The ability of tetrapeptides, but not tripeptide vinyl sulfones, to act as substrates for the proteasome suggests there could be a minimal length requirement for hydrolysis by the proteasome. These studies indicate that it is possible to generate inhibitors that are largely specific for individual beta subunits of the proteasome by modulation of the P4 and carboxy-terminal vinyl sulfone moieties.
منابع مشابه
The effect of temperature on the binding affinity of Remdesivir and RdRp enzyme of SARS-COV-2 virus using steered molecular dynamics simulation
The fatal SARS-COV-2 virus appeared in China at the end of 2019 for the first time. This virus has similar sequence with SARS-COV in 2002, but its infection is very high rate. On the other hand, SARS-COV-2 is a RNA virus and requires RNA-dependent RNA polymerase (RdRp) to transcribe its viral genome. Due to the availability of the active site of this enzyme, an effective treatment is targeting ...
متن کاملDirected Blocking of TGF-β Receptor I Binding Site Using Tailored Peptide Segments to Inhibit its Signaling Pathway
Background: TGF-β isoforms play crucial roles in diverse cellular processes. Therefore, targeting and inhibiting TGF-β signaling pathway provides a potential therapeutic opportunity. TGF-β isoforms bind and bring the receptors (TβRII and TβRI) together to form a signaling complex in an ordered manner. Objectives: Herein, an antagonistic variant of TGF-β (AnTβ)...
متن کاملBacillus Amyloliquefaciens Alpha-amylase Inhibition by Organic Solvents: A Study on Methanol, Ethanol and Propanol
Alpha-amylase is widely used as an industrial enzyme, and a therapeutic target for which inhibitors are designed. Organic solvents are used to dissolve various compounds that would be studied as moderators of alpha-amylases, but they could themselves affect enzyme activity and stability. Methanol, ethanol and propanol are simple alcohols that may be commonly used to this end, and their effect h...
متن کاملDesign, Synthesis and Evaluation of Substituted Aryl-2-Nitrovinyl Derivatives as Small Molecules Proteasome Inhibitors
Based on the existing structure activity relationship for proteasome inhibitors, a number of substituted aryl-2-nitrovinyl derivatives have been synthesized as Michael acceptor and their cytotoxicity and proteasome inhibitory effects were evaluated on two cancer cell lines. Compound 2d exhibited IC50 values of 0.71 and 17.79 μM comparable to bortezomib against MCF-7 and PC-3, respectively. The ...
متن کاملMechanism-Based Studies of the Active Site-Directed Inhibition and Activation of Enzyme Transketolase
Derivatives of phenyl-keto butenoic acids have been reported to be inhibitors of pyruvate decarboxylase, (PDC). The inhibition of transketolase, a thiamine requiring enzyme such as PDF, by meta nitrophenyl derivative of 2-oxo-3-butenoic acid (MNPB) is reported here. These studies indicate that the inhibitor binds to the enzyme at the active site. A two-step inhibition was observed, first th...
متن کاملذخیره در منابع من
با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید
برای دانلود متن کامل این مقاله و بیش از 32 میلیون مقاله دیگر ابتدا ثبت نام کنید
ثبت ناماگر عضو سایت هستید لطفا وارد حساب کاربری خود شوید
ورودعنوان ژورنال:
- Chemistry & biology
دوره 5 6 شماره
صفحات -
تاریخ انتشار 1998