Video Experimental Relacionado
Updated: May 7, 2026
07:26
Single-molecule Super-resolution Imaging of Phosphatidylinositol 4,5-bisphosphate in the Plasma Membrane with Novel Fluorescent Probes
Published on: October 15, 2016
Estructura de una familia de presenilinas proteasa aspartato intramembrana de la familia de las presenilinas
Xiaochun Li1, Shangyu Dang, Chuangye Yan
1Ministry of Education Key Laboratory of Protein Science, Center for Structural Biology, School of Life Sciences, Tsinghua University, Beijing 100084, China.
Nature
|December 21, 2012
Resumen
Este estudio revela la estructura cristalina de un homólogo de la peptidasa peptídica presenilina/señal (PSH), una proteasa intramembrana. La estructura proporciona nuevos conocimientos sobre el mecanismo de esta importante clase de enzimas.
Área de la Ciencia:
- La bioquímica es la bioquímica.
- Biología Estructural Biología estructural.
- Biología Molecular Biología Molecular
Sus antecedentes:
- La presenilina y la peptidasa de péptido de señal (SPP) son proteasas aspartilo intramembrana cruciales en los eucariotas.
- La comprensión de sus mecanismos está limitada por la falta de datos estructurales.
Objetivo del estudio:
- Para determinar la estructura cristalina de un homólogo de la presenilina/SPP (PSH).
- Proporcionar información estructural sobre la familia de las presenilinas/SPP de las proteasas intramembranares.
Principales métodos:
- Cristalografía de rayos X con rayos X.
- Determinación de la estructura de las proteínas.
Principales resultados:
- Se informó de la estructura cristalina de PSH de Methanoculleus marisnigri JR1.
- La proteasa presenta un nuevo pliegue de segmentos de nueve transmembranas con distintos dominios N-terminal y C-terminal.
- Identificó los residuos catalíticos de aspartato ubicados dentro de la membrana lipídica, accesible a través de una gran cavidad.
Conclusiones:
- La estructura determinada ofrece una base para la comprensión del mecanismo de presenilina y SPP.
- Proporciona información estructural novedosa sobre una familia clave de proteasas intramembrana.
Videos de Conceptos Relacionados
02:15Protein and Protein Structure
Proteins are one of the most abundant organic molecules in living systems and have the most diverse range of functions of all macromolecules. Proteins may be structural, regulatory, contractile, or protective. They may serve in transport, storage, or membranes; or they may be toxins or enzymes. Their structures, like their functions, vary greatly. They are all, however, amino acid polymers arranged in a linear sequence.
A protein's shape is critical to its function. For example, an enzyme can...
A protein's shape is critical to its function. For example, an enzyme can...
01:35Asymmetric Lipid Bilayer
Biological membranes show uneven distribution of different types of lipids in the inner and outer layers, resulting in transverse asymmetric membranes. The treatment of the erythrocyte membrane with the enzyme phospholipase confirmed the asymmetric nature of the lipid bilayer. The enzyme hydrolyzes lipids into fatty acids and hydrophilic groups. The phospholipase acts only on the outer layer of the membrane, while the inner layer remains intact. The phospholipase treatment resulted in 80%...
01:39Mechanism of Filopodia Formation
Filopodia are thin, actin-rich cellular protrusions that play an important role in many fundamental cellular functions. They vary in their occurrence, length, and positioning in different cell types, suggesting their diverse roles.
Their main function is to guide migrating cells during normal tissue morphogenesis or cancer metastasis by recognizing and making initial contacts with the extracellular matrix. However, they can also act as stationary cell anchors or help to establish communication...
Their main function is to guide migrating cells during normal tissue morphogenesis or cancer metastasis by recognizing and making initial contacts with the extracellular matrix. However, they can also act as stationary cell anchors or help to establish communication...
01:10Integrins
Animal and protozoan cells do not have cell walls to help maintain shape and provide structural stability. Instead, these eukaryotic cells secrete a sticky mass of carbohydrates and proteins into the spaces between adjacent cells. This network of proteins and molecules is called an extracellular matrix or ECM.
Some ECM proteins assemble into a basement membrane to which the remaining components adhere. Proteoglycans typically form the bulk of the ECM while fibrous proteins, like collagen,...
Some ECM proteins assemble into a basement membrane to which the remaining components adhere. Proteoglycans typically form the bulk of the ECM while fibrous proteins, like collagen,...
01:29Tight Junctions
Tight junctions are molecular seals between cells that prevent the leaking of fluids, ions, and other small solutes across cavities and compartments in multicellular organisms. They are mainly composed of claudin and occludin transmembrane proteins, and other proteins such as tricellulin and JAM (junctional adhesion molecule). All these proteins are 4-pass transmembrane proteins, except JAM, which is a single-pass transmembrane protein belonging to the immunoglobulin superfamily. The...
01:11Papillary Dermis
Dermis
The dermis might be considered the "core" of the integumentary system, as distinct from the epidermis and hypodermis. It contains blood and lymph vessels, nerves, and other structures, such as hair follicles and sweat glands. The dermis is made of two layers of connective tissue that comprise an interconnected mesh of elastin and collagenous fibers, produced by fibroblasts.
Papillary Layer
The papillary layer is made of loose, areolar connective tissue, which means the collagen and...
The dermis might be considered the "core" of the integumentary system, as distinct from the epidermis and hypodermis. It contains blood and lymph vessels, nerves, and other structures, such as hair follicles and sweat glands. The dermis is made of two layers of connective tissue that comprise an interconnected mesh of elastin and collagenous fibers, produced by fibroblasts.
Papillary Layer
The papillary layer is made of loose, areolar connective tissue, which means the collagen and...