Membrane Protein Crystallography

Membrane proteins play crucial roles in essential cellular processes of all organisms. Although they comprise ca. 30% of the genomic information, little information is available on membrane protein structure Structural molecular biology plays a pivotal role in modern biology, both in the fundamental understanding of living things and in the design of new treatments for disease.

Head of Laboratory

Research Interests

Membrane proteins play crucial roles in essential cellular processes of all organisms. Although they comprise ca. 30% of the genomic information, little information is available on membrane protein structure Structural molecular biology plays a pivotal role in modern biology, both in the fundamental understanding of living things and in the design of new treatments for disease.

In our group, we are currently working on the structural characterization of membrane-bound proteins and complexes, namely those involved in respiration and metabolism. We have recently solved the X-ray structure of the membrane-bound cytochrome c nitrite reductase NrfHA complex (Rodrigues et al. EMBO J, 2006), which revealed novel heme coordination motifs and provided important insights into the menaquinol binding site and electron transfer fl ow within the complex. This structure represents an important contribution to the limited number of available structures of quinone- interacting membrane complexes Work in collaboration with the Microbial Biochemistry group at ITQB (Coordinator: Dr. Inês C. Pereira). We have also solved the structure of Sulfi de:quinone oxidoreductase, isolated from the membrane fraction of an hyperthermophilic archaea. The X-ray structure showed structural homology with gluthatione reductase family and revealed the presence of a disulphide group near the FAD cofactor, which prompted for a new functional characterization (manuscript in preparation). Work in collaboration with the Metalloproteins and Bioenergetics group at ITQB (Coordinator: Prof. Miguel Teixeira). Besides respiratory and metabolic enzymes, we are also interest in membrane transport systems, which play crucial roles in essential cellular processes of all organisms. The Major Facilitator Superfamily (MFS) is one of the two largest families of membrane transporters and is found in Bacteria, Archaea, and Eukarya. MFS permeases usually comprise 12-14 transmembrane alpha helices. In general membrane transport systems are poorly understood, mostly because of the technical diffi culties involved in isolating suffi cient protein for elucidation of their structure-activity relationships. We have recently initiated a structural genomics approach on membrane transport proteins from Archaea, in collaboration with Prof. Peter Henderson (Leeds University, UK) and Dr. Arnulf Kletzin (Darmstadt University, Germany). Our main focus are MFS transporters involved in the uptake of sugars, nucleosides and amino acids; and those needed for effl ux of antibiotics.

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 Group Members

• Mª Luísa Rodrigues, Post-doc
• Meike Stelter, Post-doc
• Matteo de Rosa, post-doc IGC/ITQB
• Diana Plácido, PhD student
• José Brito, PhD student
• Tânia Oliveira, PhD student

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Selected Publications

1. Rodrigues ML, Oliveira TF, Pereira IAC and Archer M (2006). X-ray structure of the membrane-bound cytochrome c quinol dehydrogenase NrfH reveals novel haem coordination. EMBO Journal 25(24): 5951-5960
2. Rodrigues ML, Archer M, Martel P, Miranda S, Thomaz M, Enguita FJ, Baptista R, Melo E, Sousa N, Cravador A and Carrondo MA (2006) Crystal structures of the free and sterol-bound forms of β-cinnamomin” Bioch. Byophys Acta 1764: 110-121
3. Palma PN, Rodrigues ML, Archer M, Bonifacio MJ, Loureiro AI, Learmonth DA, Carrondo MA and Soares-da-Silva P (2006) Comparative study of orthoand meta-nitrated inhibitors of catechol- O-methyltransferase: Interactions with the active site and regioselectivity of O-methylation.” Molecular Pharmacology 70(1): 143-153 

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MX Unit Website

For further information please visit the MX Unit Website

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Cristalografia de Proteínas Membranares (PT)

Este grupo da Unidade de Cristalografia de Macromoléculas dedica-se particularmente à determinação de estruturas de proteínas associadas às membranas celulares e de proteínas com aplicações biomédicas. As proteínas/complexos membranares desempenham um papel fundamental nos processos biológicos de todos os organismos. Cerca de 30% da informação contida nos genomas codifica proteínas membranares. No nosso grupo, trabalhamos na caracterização estrutural e funcional de proteínas membranares envolvidas em processos de respiração, metabolismo ou transporte. Os modelos moleculares obtidos permitem-nos compreender melhor os princípios básicos da arquitectura das proteínas, bem como conhecer, num detalhe a nível atómico, os centros activos das proteínas, e as suas interacções com ligandos, substractos ou inibidores. A relação estrutura-função permite-nos propôr mecanismos reaccionais e desvendar alguns mistérios da Biologia. Esta técnica também tem sido muito útil na indústria farmacêutica e tem tido uma contribuição signifi cativa no desenvolvimento do rational drug design, ou seja, através do conhecimento da estrutura da proteína podem-se “desenhar” activadores ou inibidores para essa proteína.

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