R/PlotProteinPeptideRatio.R

In BioAlvaro/MQmetrics: Quality Control of Protemics Data

#' Identification Ratio Between Peptides and Proteins
#'
#' @param MQCombined Object list containing all the files from the MaxQuant
#' output. It is the result from using \code{make_MQCombined}.
#'
#' @param intensity_type The type of intensity of interest. Values: 'Intensity'
#'  or 'LFQ'. Default = 'Intensity'.
#'
#' @param long_names If TRUE, samples having long names will be considered, and
#'  the name will be split by sep_names. By default = FALSE.
#'
#' @param sep_names If long_names is TRUE, sep_names has to be selected. Samples
#'  names will be split. By default is NULL.
#'
#' @return
#' Returns one plot showing the proteins identified vs the peptide/protein
#' ratio in each experiment.
#'
#' @export
#'
#' @examples
#' MQPathCombined <- system.file("extdata/combined/", package = "MQmetrics")
#' MQCombined <- make_MQCombined(MQPathCombined)
#' PlotProteinPeptideRatio(MQCombined)
PlotProteinPeptideRatio <- function(MQCombined,
                                    intensity_type = 'Intensity',
                                    long_names = FALSE,
                                    sep_names = NULL){

    Experiment <- value <- variable <- r <- NULL

    proteinGroups <- MQCombined$proteinGroups.txt
    summary <- MQCombined$summary.txt

    if (intensity_type == 'Intensity') {


        df <- proteinGroups %>%
            select(contains('Intensity '))%>%
            select(-contains('LFQ'))

        #Remove Intensity from name
        colnames(df) <- gsub("Intensity.","",colnames(df)
        )
        title <- 'Proteins vs Peptide/Protein ratio based on Intensity'
    }

    if (intensity_type == 'LFQ'){

        #Remove LFQ Intensity from name

        df <- proteinGroups %>%select(contains('LFQ '))

        colnames(df) <- gsub("LFQ intensity.", "", colnames(df))

        title <- 'Proteins vs Peptide/Protein ratio based on LFQ'

        #Error if LFQ Intensity not found.

        if (length(df) == 0) {
            print('LFQ intensities not found,
                changing automatically to Intensity.')

            df <- proteinGroups %>%
                select(contains('Intensity ')) %>%
                select(-contains('LFQ'))

            #Remove Intensity from name
            colnames(df) <- gsub("Intensity.", "",
                                            colnames(df))
            title <- 'Proteins vs Peptide/Protein ratio based on Intensity'
        }
    }

    df <- data.frame("Proteins Identified" = nrow(df)-colSums(df==0))

    df$Experiment <- rownames(df)

    rownames(df) <- NULL

    # Add column peptides identified, and peptide/protein ratio.

    MaxQuant_version <- MQCombined$parameters$Value[
        MQCombined$parameters$Parameter == 'Version']

    #Detect MaxQuant Version to read column names accordingly.

    if (MaxQuant_version == '1.6.17.0') {

        df2 <- summary %>% select(contains(c('Experiment',
                                             'Peptide Sequences Identified')))
    } else{
        df2 <- summary %>% select(contains(c('Experiment',
                                             'Peptide sequences identified')))
        colnames(df2)[
            colnames(df2) == "Peptide sequences identified"
            ] <- "Peptide Sequences Identified" # Rename column
    }

    df_merged <- merge(df, df2, by = 'Experiment')

    df_merged$`Peptides/Proteins` <- format(round(
        df_merged$`Peptide Sequences Identified` /
            df_merged$Proteins.Identified, 1), nsmall = 1)

    df_merged$`Peptide Sequences Identified` <- NULL

    df_melt <- melt(df_merged, id.vars = 'Experiment')

    d1 <- df_melt[df_melt$variable == 'Proteins.Identified',]
    d2 <- df_melt[df_melt$variable == 'Peptides/Proteins',]

    p1 <- ggplot(d1,  aes(x = Experiment, y = as.numeric(value),
                                group = variable))+
                ggtitle(title)+
                theme_bw()+
                ylab('# Proteins Identified')+
                theme(axis.text.y=element_text(colour="#FC766AFF"))+
                geom_point(colour = '#FC766AFF', size = 2)+
                geom_line(colour = '#FC766AFF', size = 1.5)#+
                # theme(panel.border = element_blank(),
                #     panel.grid.major = element_blank(),
                #     panel.grid.minor = element_blank(),
                #     axis.line = element_line(colour = "black"))

    p2 <- ggplot(d2,  aes(x = Experiment, y = as.numeric(value),
                                group = variable))+
            theme_bw()+#%+replace%
            theme(panel.background = element_rect(fill = NA))+
            ylab('Ratio Peptides/Proteins Identified')+
            theme(axis.text.y=element_text(colour="#5B84B1FF"))+
            geom_point(color = '#5B84B1FF',size = 2)+
            geom_line(colour = '#5B84B1FF',size = 1.5)+
            theme(panel.border = element_blank(),
                panel.grid.major = element_blank(),
                panel.grid.minor = element_blank(),
                axis.line = element_line(colour = "black"))

    if (long_names == TRUE) {
        p1 <-  p1 + scale_x_discrete(labels = function(x) {
                        stringr::str_wrap(gsub(sep_names," ", x),3)})


        p2 <-  p2 + scale_x_discrete(labels = function(x) {
            stringr::str_wrap(gsub(sep_names," ", x),3)})
    }

    # Get the ggplot grobs
    g1 <- ggplotGrob(p1)
    g2 <- ggplotGrob(p2)


    # Grab the panels from g2 and overlay them onto the panels of g1
    pp <- c(subset(g1$layout, grepl("panel", g1$layout$name), select = t:r))
    g <- gtable_add_grob(g1, g2$grobs[grepl("panel", g1$layout$name)],
                            pp$t, pp$l, pp$b, pp$l)


    # Function to invert labels
    hinvert_title_grob <- function(grob){
        widths <- grob$widths
        grob$widths[1] <- widths[3]
        grob$widths[3] <- widths[1]
        grob$vp[[1]]$layout$widths[1] <- widths[3]
        grob$vp[[1]]$layout$widths[3] <- widths[1]

        grob$children[[1]]$hjust <- 1 - grob$children[[1]]$hjust
        grob$children[[1]]$vjust <- 1 - grob$children[[1]]$vjust
        grob$children[[1]]$x <- unit(1, "npc") - grob$children[[1]]$x
        grob
    }

    # Get the y label from g2, and invert it
    index <- which(g2$layout$name == "ylab-l")
    ylab <- g2$grobs[[index]]                # Extract that grob
    ylab <- hinvert_title_grob(ylab)


    # Put the y label into g, to the right of the right-most panel
    # Note: Only one column and one y label
    g <- gtable_add_cols(g, g2$widths[g2$layout[index, ]$l], pos = max(pp$r))

    g <-gtable_add_grob(g,ylab, t = min(pp$t), l = max(pp$r)+1,
                        b = max(pp$b), r = max(pp$r)+1,
                        clip = "off", name = "ylab-r")


    # Get the y axis from g2, reverse the tick marks and the tick mark labels,
    # and invert the tick mark labels
    index <- which(g2$layout$name == "axis-l")    # Which grob
    yaxis <- g2$grobs[[index]]                  # Extract the grob



    plot_theme <- function(p) {
        plyr::defaults(p$theme, theme_get())
    }


    # Put the y axis into g, to the right of the right-most panel
    # Note: Only one column, but two y axes - one for each
    # row of the facet_wrap plot
    g <- gtable_add_cols(g, g2$widths[g2$layout[index, ]$l], pos = max(pp$r))

    nrows = length(unique(pp$t)) # Number of rows
    g <- gtable_add_grob(g, rep(list(yaxis), nrows),
                        t = unique(pp$t), l = max(pp$r)-1,
                        b = unique(pp$b), r = max(pp$r)+0)

    # draw it
    return(grid.draw(g))
}