Indice degli argomenti

  • 1. PHYSICS/BIOLOGY/COMPUTATION:SETTING THE STAGE

    LECTURE N.1 sep 25 2023

    Basic biology and computational biophysics, at the molecular level: The space of sequences as the archive of molecular evolution (Zuckerkandl&Pauling1965)

    Models/Computation/Simulation

     Deterministic/stochastic simulations (Bray2015)

     Probabilities as conditional probabilities (van_de_Schoot2021)

    Direct vs inverse problems

    Biophysics in the XXI century: from molecular to integrative, evolutionary biophysics (an example:Terry Hwa): semantics: biological physics/physical biology; biologically inspired physics/biophysics

    Physics of living systems vs physics of parts of living systems (Ageno’s [integrative] vs Careri’s [molecular] approaches)

    Simplicity/complexity

    Complex systems (layers and scales: “More is different”, Phil_Anderson1972) and living systems

    Big data, the problem of “law without law” and the end of theory (readings: Wheeler1983, Caprara_Vulpiani2018)

     The manifesto of the big data and artificial intelligence era (Chris_Anderson2008)

    Top-down vs bottom-up approaches

    (suggested general readings: Richard Holmes, The Age of Wonder: How the Romantic Generation Discovered the Beauty and Terror of Science (Published by HarperPress in 2008 ISBN 978-0-00-714952-0); Siri Hustvedt, “The Delusions of Certainty”, Simon & Schuster (ed. it. Le Illusioni della Certezza,Einaudi, 2018); Dennis Bray, “Wetware”, Yale University Press,2009 this is a rem book by one of the pioneers of systems biology)

     (suggested general readings: Siri Hustvedt, “The Delusions of Certainty”, Simon & Schuster (ed. it. Le Illusioni della Certezza,

    Einaudi, 2018); Dennis Bray, “Wetware”, Yale University Press,2009)


    STUDY MATERIALS

    slides CB_23_24_L1.pdf

    further reference material in the CB_23_24_PACK_1

    consider the text CB_23_24_Inaugural.pdf for a general discussion



    • FIND, HERE COLLECTED, THE STUDY MATERIALS AND SUGGESTED READINGS TO SET THE GENERAL STAGE OF THE COURSE

  • 2. FROM THE SCHROEDINGER EQUATION TO MOLECULAR DYNAMICS

    LECTURES N.2 AND 3, SEP 26 and 28 2023.

    -Molecular structures and the Born-Oppenheimer approximation
    -Basic principles of Ab-initio Molecular Dynamics: Born-Oppenheimer surfaces
    -Hellman-Feynman Theorem

    MODELLING ε0(R) ---> FORCE FIELDS

    Morse potential as the simplest force field

    Force field as a network (just the concept)

    Pairwise additive approximation

    General form of a force field: bonded terms/non bonded terms

    BIBLIOGRAPHY
    Tuckerman_Born-Oppenheimer.pdf
    Griebel2007_Numerical Simulation in Molecular Dynamics_Chap2.pdf [S]
    Feynman1939,pdf [R]

  • 3. COMPUTABILITY

    LECTURE N. 4 MON OCT 2 2023 

    Computation as an INPUT/OUTPUT process

    Finite states machines

    Effective procedures and computability of functions: algorithms

    Non computability

    Top-down / bottom-up methods

    Study materials:

    Chapter n.3 of Feynman’s lectures in Computation (1996)

    See also, Computational models of science, chap 9 of Jean-Gui Meunier, Computational Semiotics (2021)




    • from Feynman's Lectures on Computation chap. 3

      from Meunier's Computational Semiology chap.9

  • 4. THE BIOLOGICAL SETTING

    Lecture N. 5 TUE OCT 5 2023 room 8 12am-2pm

    biological physics/physical biology; biologically inspired physics/biophysics

    evolutionary distances (slides CB_22_23_L4.pdf, integrate with further self-study)

    genomes and the genetic code: Central dogma of molecular biology, informational biomolecules: nucleic acids & proteins: peptide bonds formation and planarity, protein synthesis on the ribosome, genetic code and its degeneration (codon bias) (HA 2.2, 2.3)

    what is darwinian evolution (HA 3.1,3.2, 3.3 (mutations), 3.4 (coalescence) 3.6 (neutral evolution and adaptation, codon bias))

    the space of biological sequences as the archive of evolution (molecules as documents of evolutionary history, see: ZuckerkandlPauling1965

    molecular evolution of nucleotide sequences

    essential genes, homologous/paralogous genes

    evolutionary distances d vs. sequence identity D

    sequence/structure/dynamics/function


    • Find here materials to complement the track of this lectureN.4: In particular the introductory chapter of Weinberg's treatise on Cancer and the interesting paper Physics is life by Goldenfeld and Woese.

  • 5. MODELS OF SEQUENCE EVOLUTION

    lectures N.6, 7, 8 and 9

    Life is physics (Goldenberg-Woese)

    What is evolution (HA 3.1), the naïve setting: mutation-selection (HA 3.2)

    Species/speciation

    The space of biological sequences as the archive of evolution (Molecules as documents of Evolutionary History (see: ZuckerkandlPauling1965)

    Mutations (HA 3.2), sequence variation within and between species (HA 3.3)

    Negative purifying vs positive Darwinian selectionEevolutionary pressure on a site through dn/ds [Ka/Ks] (optional) (HA 11.2.3)

    Evolutionary distances between orthologous genes (HA 4.1.1)

    Probabilistic models of evolution (DU chap 8.2)

    The Jukes-Cantor model (HA 4.1.2 and Box 4.1)

    Generative probabilistic models of sequence evolution: general scheme (HA 4.1)

    Alphabets, symbols, states

    Transition rates matrix

    Dynamics between states: Master equations: in /out terms

    Detailed balance

    Alignments (genes/proteins)

    Orthology paralogy, homology

    The genetic code: codon bias

    Why probabilistic evolutionary models?

    substitution matrices (DU 2.2, Protein Substitutions Models (slides))

    PAM model of protein sequence evolution (HA 4.2)

    PAM distances (HA box 4.2)

    Log-odd scoring PAM matrices (HA 4.3.1, DU chap 2)

    BLOSUM scoring matrices (HA 4.3.3, DU chap.2)

    STUDY MATERIALS IN CB_23_24_PACK_5




  • 6. PROTEINS: BETWEEN ORDER AND DISORDER

    LECTURES: N, 10, 11, 12, 15 and 16

    PROTEINS BETWEEN ORDER AND DISORDER

    Primary, secondary, tertiary and quaternary protein structures

    Cellular Crowding, Chaperones, Co-translational folding/assembly

    Standard form of the 20 naturally occurring amino acids: chirality of amino acids, formation of the peptide bond

    Special amino acids: glycine, histydine, proline, cysteine (disulphide bridges)

    Dihedral angles and Ramachandran plots: regions of standard secondary structures

    Stabilizing forces in protein structure (electrostatic, van der Waals, hydrogen bonds, hydrophobic,…)

    Water and protein conformations: role of hydrogen bonds

    Principles of evolutionary protein design: positive/negative design

    What is bioinformatics

    Protein Data Bank (PDB): to visualize protein structures use Pymol, Chimera, Litemol on the .pdb files (see The language of the protein universe by M. Levitt)

    free energy and the folding processstructural and functional protein domains (what is a protein domain? see also as a suggested reading: Pawson’s interaction domains, Pawson2002).

    sequences determine protein structures (suggested reading: Anfinsen’s dogma, Anfinsen1973) and structures are more conserved than sequences

    proteins: between order and disorder. CH plot (Uversky2002)

    intrinsically disordered proteins (see databases: DISPROT, MobiDB)

    Dihedral angles and Ramachandran plots: regions of standard secondary structures

    Stabilizing forces in protein structure (electrostatic, van der Waals, hydrogen bonds, hydrophobic,…)

    Water and protein conformations: role of hydrogen bonds

    Principles of evolutionary protein design: positive/negative design

    SUPERPOSING PROTEIN STRUCTURES

    Structural distances and philogenetic distances

    How to superpose protein structures in general (hard problem)

    Subtract roto-translations + RMSD

    Quaternions and rotations

     
    STUDY MATERIALS IN CB_23_24_PACXK_6

  • 7. MOLECULAR DYNAMICS OF PROTEINS

    LECTURES N. 13, 14, 17 and 18

    lecture 18 was devoted to the setup of  a project on the comparison of the dynamical structure of native and mutated viral lysozymes

    initial conditions, integration schemes, force fields, integration schemes, thermostats

    biological energy scales/biological time scales/ timescales of protein motions

    protein folding in vivo (crowding) / in vitro

    free energy barriers control relaxation times

    protein disorder/protein order in the simulation (solid-like vs liquid-like motions)

    quantum mechanics vs Molecular Mechanics

    force fields: bonded + nonbonded parametrisation (see also lecture N. 3)

    energy minimisation and the protein folding problem (recent application of AI: ALPHA FOLD 2)

    typical observables in a protein MD simulation: RMSD(t), RMSF(t), Rg(t)

    structural superposition of proteins

    the problem of roto-translation subtraction

    symplectic integrators, Verlet's algorithm: remarks on the Liouville’s formulation of the discretized dynamics

    (Tsai2004,  Binder_Ciccotti1996.pdf, Schiller2008)

    Trotter product formula of operators

    CONTROLLING TEMPERATURE AND PRESSURE IN MD

    MD as generator of thermodynamical statistics, overview

    Liouville formulation of the MD, factorization

    Ensembles

    Constant temperature MD: quenches, Anderson Thermostat, Nosè-Hoover Thermostat

    Temperature Echo


    CB_23_24_PACK_7 



    • Slides and supplemtary materials for the core lectures in MD of proteins

  • 8. DATA ANALYSIS AND MOLECULAR DYNAMICS: PCA AND COLLECTIVE COORDINATES

    LECTURES N. 19 and 20

    Introduction to Principal Components Analysis (PCA) 

    Dealing with multivariate contexts in which several correlated variables interfere in a phenomenon, the idea is to

    LINEAR transform the original variables into uncorrelated ones that are ordered following their variance. The low variance transformed variables can be neglected, realizing a dimensional compression of the initial data.

    Protein essential dynamics as PCA. The principal components associated to the multi-dimernsional protein dynamics are 

    collective coordinates of potential biological meaning.

    STUDY MATERIALS IN CB-23_24_PACK_8

    • Slides and supplementary materials on PCA Essential Dynamics of proteins, collective coordinates 

  • 9. NETWORKS

    LECTURE N. 21 and 24 (extremely compressed, here and in the PACK find reference to materials that were mentioned)

    simplicity/complexity/scales (Anderson1972)

    micro/meso/macro scales: objects studied in diluted isolation (e.g. in vitro) and connected into a network of relationships (e.g. in vivo) , see Parisi's 2021  Nobel Lecture.

    networks as a general model for complex systems.

    structure meets networks at the nanoscale : Hi-C maps and the chromatin structure, see Kempfer_Pombo2019
                  

    elements of network models:  nodes, links, adjacency matrices, degree distributions, power-laws (scale free-networks), communities [min-cut theorems] 


    Communities (Fortunato2016)

    suggested general textbook: Vito Latora, Vincenzo Nicosia and Giovanni Russo, Complex Networks, Cambridge University Press 2016

    (see in particular chapters 2 and 9)

    inner networks in proteins structures and sequences (see Vendruscolo2002, Sladek2021, Estrada 2010)

    Recurrence Quantification Analysis as an inner correlation/information network in physiological signals and proteins

    (https://en.wikipedia.org/wiki/Recurrence_quantification_analysis)

    protein-protein networks, interactomes (see STRING database (https://string-db.org/))

    interactomes as information networks (see cancelled CENTURI 2021 Cargese meeting: https://centuri-livingsystems.org/csm2021/)

    STUDY MATERIALS IN CB_23_24_PACK_9

  • 10. INTRODUCTION TO THE STRUCTURAL BIOLOGY OF NUCLEIC ACIDS

    LECTURES N. 22 and 23

    GUEST LECTURER Dr. Andrea Cappannini from the LABORATORY OF BIOINFORMATICS AND PROTEIN ENGINEERING (https://genesilico.pl) WARSAW PL

    In the attached file you will find a list of the topics that have been discussed and an updated bibliography

  • 11. CLUSTER ANALYSIS

    LECTURES N.25 and 26 and 27

    clustering (HA, 2.6 hierarchical vs partitioning methods, see also Altman2017).

    distances, metric spaces

    density based (topological) vs coupling (interaction) based methods

    k-means, Dbscan, superparamagnetic (Domany2003)

    information based methods (Bialek2004, Slonim2005, Luksza2010)

    comparing clusterings: the mutual information approach (Meila2007, Vinh2010)

    Partitioning clusterings as random fragmentation processes: breaking of self-averaging

    (see: Andrea De Martino, The Geometrically Broken Object, 1998 https://arxiv.org/abs/cond-mat/9805204)

    STUDY MATERIALS IN CB_23_24_PACK_10

    • Find in the PACK the papers referred to in the discussion and pdf files of the lectures on clustering that were used in the CB course of 2021.

  • 12. BAYESIAN MACHINE LEARNING

    LECTURES N. 28, 29 and 30

    Relevance of Bayes’ theorem in the analysis of sequences

    (HA 10.2, bayesian model (parameter) selection: pseudo counts

    generative probabilistic models

    Markov order 0 models (urn models)

    A bayesian classifier of disordered proteins ( a critique of, look at the priors (Bulashevska2008)

    Entropy rules from Baldi and Brunak)
    Bayes Factors in model selection: the relevance of priors (see HA  eq. 10.5 and box 10.1)

    STUDY MATERIALS AND SUGGESTIONS FOR PERSONAL STUDY IN CB-23_24_PACK_11

    • Find here the slides that were used to introduce the discussion and materials for personal study

  • 13. HIDDEN MARKOV MODELS

    LECTURES N. 33, 34, 35 and 36

    Prior and posterior probabilities (key formula10.3), pseudocounts (key formula 10.11)


    Hidden Markov Models(HMM): basic structure (HA 10.3, see also Chap3_Durbin_Biological_Sequence_Analysis)

    HMM Problems:Evaluation, Decoding, Learning (see slides: Introduction_Hidden_Markov_Models.pdf)

    
Decoding problem: the Viterbi algorithm (HA box 10.2)
Training supervised/unsupervised of a HMM on a gapless profile associated to a protein family: Viterbi (minimum action path) vs Baum-Welsch (path integral) method (HA 10.3.3).

    Forward/Backwards algorithms.

    • Slides of the lectures on the structure and training of Hidden Markov Models

  • 14. INTRODUCTION TO SYSTEMS BIOLOGY: THE GILLESPIE ALGORITHM

    LECTURES N. 31 and 32

    Introduction to Systems Biology

    The chemical Master Equation

    The Gillespie Algorithm

    SEE THE SLIDES OF THE LECTURES IN CB_23_24_PACK_13

  • MOLECULAR DYNAMICS PROJECT